Copyright © 2017 by Roland Stull. Practical : An Algebra-based Survey of Atmospheric Science. v1.02b

INDEX

1-D normal shock, 572-574 Look for Patterns, 107-109 droplets, 191-192 1-leucine, 195 Mathematics & Math Clarity, 393, 762 nuclei, 192-196 1-tryptophan, 195 Model Sensitivity, 350 active 1,3-butadiene, 725 Parameterization Rules, 715 , 162 1,5-dihydroxynaphlene, 195 Problem Solving, 869 remote sensors, 219 1.5 PVU line, 364, 441, 443 Residuals, 340 tracers, 731 2 ∆x , 760-761 Scientific Laws - The Myth, 38 adaptive, 771 2 layer system of fluids, 657-661 Scientific Method, 2, 343 adiabat, 17 3 second rule between lightning and thunder, 575 Scientific Revolutions, 773 dry, 63, 119-158, 497 3DVar data assimilation, 273 Seek Solutions, 46 moist (saturated), and on thermo diagrams, 119- 4DVar data assimilation, 273 Simple is Best, 680 158 5-D nature of weather, 436 Toy Models, 330 adiabatic 5th order rainbow, 840 Truth vs. Uncertainty, 470 cooling, 60-64, 101-106 9 degree U.S. Supreme Court Quotation, 470 to create clouds, 159-161 halo, 847, 854-855 A-grid, 753 effects in frontogenesis, 408-411 Parry arc, 855 abbreviations for excess water variation, 187 18 degree halo, 847, 855 airmasses, 392 lapse rate, 60-64, 101-106, 140, 880 20 degree halo, 847, 855 chemicals, 7 dry (unsaturated), 60-64 22 degree clouds, 168-170 moist (saturated), 101-106 angles, estimating, 847 METARs and SPECIs, 208, 270 process, 60, 121 halo, 842, 845-846, 854-855 states and provinces, 431 on thermo diagrams, 121, 129 Lowitz arc, 855 time zones, 5 vertical movement, 60 Parry arc (upper, lower, suncave, sunvex), 854- weather-map symbols, 168-170, 208, 274-279, 614- warming, 60 855 615 in downslope winds, 676-677 23 degree halo, 847, 855 ABI (advanced baseline imager) on satellite, 222-235 adjacent faces of ice crystal, 842 24 degree halo, 847, 855 abrupt climate change processes, 810-812 adjustment 30-year average climate, 354, 355, 358, 816 abscissa - defined, 3 geostrophic, 343-349 30-30 rule for lightning safety, 570 absolute part 1, 344 35 degree halo, 847, 855 angular momentum for hurricanes, 617 part 2, 349 40-year natural hurricane cycle, 631 circulation, 366 part 3, 404-407 44 degree parhelia, 855 humidity, 91 moist convective, 70 46 degree definition, 14, 91 Admiral Beaufort, 635 halo, 842, 846, 854-855 measurement, 97, 111 Adriatic Sea, bora winds, 675 Lowitz arc, 855 saturated, 91 ADT, Atlantic daylight time, defined, 5 Parry arc (infralateral, supralateral), 854-855 phase speed, 658 advanced baseline imager (ABI) on satellite, 222-235 53rd Reconnaissance Squadron (hurricane hunters), stability, 140 advection, 65 637 temperature, 7 adiabatic, 411 100-50 kPa thickness charts, 345-349, 436, 439, 442 virtual temperature, 14-15 cold air, 349 120° parhelia (or paranthelia), 854-855 vorticity, 363, 448 differential, and castellanus clouds, 164 advection of, 448 definition, 65-67 zero, 879 flux, 34-35, 65-67, 107 absolutely stable or unstable, 140 , 173-177 absorptance, 225 force, 294-295 A absorption heat, 65-67, 714 A Scientific Perspective (see summary in Appendix bands, 221 of TKE by mean wind, 708 A), 877 hygrometer, 111 mass, 317-318, 465 Be Creative, 288, 293 lines, 221 max, as found on weather maps, 458 Be Meticulous, 20 of light, 833 moisture, 107 Be Safe, 485, 517, 567, 570, 583-584 of radiation, 41-43, 219-226 momentum, 294-295 Cargo Cult Science, 167 window, 43, 220, 796 numerical stability, 760-761 Check for Errors, 16 absorptivity, 41 related to pressure tendency, 465 Citizen Scientist, 738 and Beer’s Law, 43 role in katabatic wind, 653 Consequences, 218 and Kirchhoff’s Law, 41, 220 temperature, 65-67 Creativity in Engineering, 288 of atmosphere, 41-43 self-development of , 468-469 Data Misinterpretation, 729 ac (altocumulus clouds), 168 turbulence, 708 Descartes and the Scientific Method, 2, 343 ACARS (aircraft communication & reporting sys- turbulent heat, 714 Ethics and Data Abuse, 826 tem), 272 term, 747 Expert vs. Novice, 72 accas (altocumulus castellanus clouds), 168 vorticity, 447-451 Give Credit, 24 acceleration by thermal wind (), 456-462 Great Scientists Make Big Mistakes, 863 definition, 292 warm air, 349 Have Passion, 877 gravitational, 15 water, 107 in Newton’s second law, 292, 301, 314, 746-749 advective vertical, 315, 554, 746 clouds (stratiform), 94, 164 accessory clouds, 168-169 flux, 34-35, 65, 107, 294 accretion (or riming), 205 force, 294 accumulated heating or cooling, 394-395, 693-694 aeolian tones, 560 calculation of, 693-694 aerodynamic in , 176-177 drag on falling role in thunderstorm formation, 528 droplets, 202 “Practical Meteorology: accumulation hailstones, 204 An Algebra-based Survey mode for CCN, 188 ice crystals, 842 of Atmospheric Science” -total rainfall, 257 rain drops, 203 by Roland Stull is licensed under a Creative accuracy roughness length, 677-678, 700-703 Commons Attribution-NonCommercial-Sha- error definition, 875 typical values, 700 reAlike 4.0 International License. View this of forecasts, 777 aerosol(s) achieved heat transport globally, 339 definition, 188 license at http://creativecommons.org/ acid rain, 567, 742 feedbacks for climate change, 811 licenses/by-nc-sa/4.0/ . This work is avail- actinometers (radiometers), 45-47 haze, 193 able at https://www.eoas.ubc.ca/books/ action, take protective, 785 scattering of radiation by, 221, 856-858 Practical_Meteorology/ activated stratospheric, and climate change, 805, 856-858 881 882 INDEX A

swelling, 193 creation, 392-397 units, 870 African easterly jet (AEJ) and waves, 611-612 definition, 391 ampere, 564, 870 age depth of cold air, 404-406 amplified response (positive feedback), 806-808 Calabrian, 799 formation region map, 392 amplitude of ice, 795, 798-799 fronts at boundaries of, 397 Kelvin , 634 Ionian, 799 genesis, 392-397 meridional displacement, 373-374 Tarantian, 799 growth rate, 394-397 mountain lee waves, 666-668 ageostrophic locations, 392 oscillations, 818 definition, 304, 314, 343, 454 maritime tropical, 392 Rossby waves in lee of mountains, 444 during approach to geostrophy, 304 modification, 397-399 AMSU (advanced microwave sounding unit), 273 flow, 343, 462, 454-462 via flow over mountains, 398-399 anabatic dynamic frontogenesis, 412 via surface heat fluxes, 397-398 cumulus clouds, 649-650 right-hand rule, 455 movement, 397 horizontal pressure gradient force, 650-652 wind , 304, 314, 454-462 residence times, 392 wind, 649-652 direction of, 455 temperature at distance from origin, 398 high-pressure associated with, 391, 650-651 equations, 314, 454 thickness, 394-397, 404-406 anafront, 404 aggregation thunderstorms, 481-482, 486 analysis in cold clouds, 205 energy released by, 499 data assimilation, 762, 765-767 in thunderstorms, 546 triggering. Convective temperature., 526- definition, 267, 280-281, 762 of ice crystals into snowflakes, 200, 202, 206-207 527 in case study, 768-770 processes, 204-205 airplane field, 763-765 Agung volcano eruption, 805 bumpy ride in, 649, 667 initial conditions, 293, 762 air mass of air inside, 23 objective methods, 280, 766-767 characteristics, constants & parameters, 880 pitot-static system for airspeed, 674 3DVar and 4DVar, 273, 767 composition, 7 shadow, white disk centered on (glory), 860 optimum interpolation, 766 conditioning, 116 window, pressure against, 21 variational, 273, 767 denisty, 10 airport verifying, 769 forecast equation for, 746 CYVR (Vancouver Internat. Airport in Canada), weather map, 274-281, 425-470 standard (STP), 880 647 hand (subjective; manual), 279-281, 402 drag, 700-702 KJFK (JFK Airport in New York), 563 methods, 274-281, 402 mass (see airmass), 389-399 routine meteorological report (METAR), 268-279 numerical, 762 conservation, 317-319, 660 runway visual range (RVR), 270 surface, 267, 402 mass of, 10 runways vs. wind direction, 646-647 analytical solution, 749 molecular weight, 7 special meteorological report (SPECI), 268-279 anemometers, 219, 321-322 molecule, scattering of light by, 220-222, 856-858 wind-shear sensors, 563 aneroid barometer, 19 parcel, 57, 59, 687-688 AIRS (atmospheric infrared sounding), 273 angle adiabatic movement, 58-64 airspeed, using pitot-static system, 674 azimuth, 4 angular momentum of, 360-361 AKDT & AKST, Alaska daylight & standard times, 5 solar, 33 buoyancy, 135, 649, 687-688 between definition, 11, 57 Alaska, 431 Earth and perihelion (=true anomaly), 28-30, follows isentropes, 144 current, 175 802 rise, 129-130, 648-649 time zone, 5 Earth and vernal equinox (=true longitude), temperature and humidity, 128 albedo, 42, 44, 793-794 801 static stability method, 138-139, 687-689 average global, 42, 793-794 perihelion and vernal equinox, 801 vs. environment, 59, 134-141 Bond, 831, 879 component, 836 water in, 99-106 geometric, 831, 879 conventions in math & meteorology, 2 pollution dispersion (see also pollution), 7, 723- ice-albedo feedback, 808-812 critical, 837 744 in daisyworld, 813-815 elevation, 4-5 brown cloud, 857-858 Moon, 42 solar, 32 episodes, 741 typical values, 42, 794 hour, 40-41, 801-802 events, 725, 741 Alembert, Jean le Rond d’, 759 incidence, 833 exceedences, 725 Aleutian mean anomaly, 29 thermo diagrams for, 151, 157-158 low, 354-356 of turbine blades, 647-648 trapped in highs, 390 time zone, 5 plane, definition of units, 870 pressure, 7-10 Alexander of Aphrodisias, 841 refraction, 833-834 quality standards, 7, 725 Alexander’s dark band, 841 solar declination, 30-31 for individual gases, 7, 725 aligned coordinate, 727 solar aximuth & elevation, 32-33 index, 743 Al-Khalili, Jim, 754 solid, definition of units, 870 USA, Canada, EU and UK, 7, 725 Allick, Susan Krueger, 639-640 true anomaly, 29 refractive index, 834-835 along wedge, 843, 845-847, 855 specific heats, 53-56, 880 shore coastal low-level jet, 664-665 zenith, 4-5 stagnation (events), 559, 741 valley winds, 653-654 ångström unit of distance, 870 aircraft alpha time zone (Europe), 5 angular airspeed, using pitot-static system, 674 alphanumeric weather codes, 268-269 frequency, 36 commercial, weather observations by, 272 alpine ski snow, 209 momentum, 360-361 communications & reporting sys. (ACARS), 272 alternative coordinates, horizontal & vertical, 746- conservation of, 360-361 glory, 860 747 equation, 360 hurricane hunter, 637 alternate faces of ice crystal, 842 of hurricane, 617 radars, 243 altitude of , 577 severe-weather hazards, 529, 556, 563 cooking time vs, 90 Rossby wave transport, 375 downbursts and gustfronts, 556, 563 key, for thunderstorms, 496-499 subtropical jet, effects on, 360-361 sounding, 134, 496 pressure change with (see height), 3, 8-9, 12-13, rotation rate of Earth, 297 turbulence experienced by 16-17 anisotropic, 708 boundary layer, 649 alto prefix, 163 turbulence, 708, 710, 727 clear-air, 141-142, 165 weather-map symbols for, 277 annual convective, 483, 498, 508 altocumulus, 134, 162-163, 168 mean global energy budget, 797 mountain wave, 667 castellanus, 162, 164-165 worldwide, 209 wind shear; gust fronts at airports, 560-563 altostratus, 134, 162-164, 168 anomalous propagation of radar beam, 244-245 wings, flow over, 88 AM anomaly, 777 AIREPS, 272 radio, static on, 568 climate, 818, 821 airmass(es), 389-399 satellite, 229 correlation, 779-780 abbreviations for, 392 ambient air-quality standards, 725 mean & true, for orbit of earth, 29 arctic vs. Antarctic, 392, 396 Amdahl, Gene, 763 warm sea surface (for ENSO and PDO), 818-820 atmospheric boundary layers are, 691 Amdahl’s Law, 763 weather, 777 blocking/damming by mountains, 397 AMDAR (aircraft meteorological data relay) code, Antarctic boundary layers are, 393-397 269, 272 airmass boundaries = fronts, drylines, 397, 416 American geography, 431 code, 392 thunderstorm triggers, 525-526 amino acids as ice nuclei, 195 katabatic winds (downslope flow), 396, 652, channeling by mountains, 397 ammonium sulfate, 190-192 676 characteristics of, 391 amount of circle, 31 classification, 391-392 clouds, 170 oscillation (AAO), 824 codes for, 391-392 substance, 870 antenna dish, radar, 240 continental polar, 392 flowing through area, 34-35 anthelic A R. STULL • PRACTICAL METEOROLOGY 883

arc, 855 dipole anomaly, 824 encroachment method for ML growth, 697-698 point, 841 oscillation (AO), 818-819, 824 entrainment anthelion, 855 arcus, 482, 562 velocity, 697-698 anthropogenic, 723, 811 area in a sounding, for CAPE & DCAPE, 503-508, zone, 692 climate change, 812 557-558 fair weather, 69-70, 690-692 clouds, 166 ARFOR code, 269 flux-ratio method for entrainment, 698 greenhouse gases, 796, 811-812 argon, Ar, 7 fogs within, 159, 173-177 pollutants, 723 Aristotle, 2, 26 formation, 13, 689-692 (see also highs, H), 389-391 arrangement of clouds, 169 free atmosphere above top of ABL, 687-692 airmass creation within, 389-399 as (altostratus clouds), 168 free , 704 aloft in hurricane core, 613 ascending friction velocity, 677-678, 700-713 atmospheric boundary layer within, 690-692 air parcels, 129-130 fuel tank for thunderstorms, 499-502, 547-548 convergence at top of, 391 motion in cyclones (lows), 356 gradient (BLG) wind, 309-311 definition, 390 node, 228-229 heat flux profiles, 698 divergence at bottom of, 390, 691 ASDAR (aircraft to satellite data relay), 272 highs, relationship to, 390 dynamics, 391 ash, volcanic, 170 hurricane, 618-620 formation locations, 391 ASOS (Automated Surface Observing System), 271 triggering by easterly wave, 611-612 isobars around, 390 aspect ratio, 485 internal, thermal (TIBL), 654-657 maximum height/pressure variation nearby, of ice crystals, 200 inversion at top of, 496-499, 522-525, 687-692 306-307 of thunderstorm cells, 485 jet, nocturnal (low-level), 699-700 mesoscale, 391 aspirated psychrometer, 94 katabatic winds at night, 696 midlatitude, 331, 390-391 assimilation, data, 765-767 kinematic heat flux, 698 polar, 391 AST, Atlantic standard time, defined, 5 location, thickness, 13 ridges, relationship to, 390 astronomical log profiles of wind, 702-703 structure , 390-391 influences on climate variability, 797 mixed layer (ML), 690, 692 subsidence within, 390, 691 Milankovitch theory, 797 growth rate, 697-698 subtropical, 391 twilight, 33-34 kinematic heat flux profile, 698 tilt with altitude, 390 unit (au or ua), 28, 870 smoke dispersion within, 735-737 vertical structure, 391 asynoptic observation data, 758 modification near frontal zone, 70-71, 691-692 weather associated with, 390, 691 Atlantic neutral, statically, 300, 308, 319 winds around, 305-307, 390, 691 multi-decadal oscillation (AMO), 824 smoke dispersion within, 732-733 anticyclonic North Atlantic oscillation (NAO), 818-819, 824 smoke plume rise within, 732-733 radius of curvature, 304-306 South Atlantic Subtropical High, 354 standard deviations for, 707 winds, 306-307, 311 time zone, 5 winds, 702 antimountain wind, 653 atlas of clouds, 168 nighttime/nocturnal (stable), 692 antipodal point, 838 atm, atmospheres, a pressure unit, defined, 7 accumulated cooling, 693 antisolar atmosphere, 1-26 jet, 699-700 arc, 855 one-layer, 795 Obukhov length, 703 point, 837 radiative models for climate, 795-797 parameterizations, 714-716 antitriptic wind, 312-313, 663 standard, 11-13, 688-690 in NWP models, 751 antivalley wind, 654 atmospheric potential temperature vs. height, 690, 692 anvil attenuation factor in the radar eq., 245-246 standard deviations for, 707 cloud, 482-484 bending of light, 861-863 profiles of variables, 692, 702-705 conditions, 489 composition, 7 pumping, 319-320 debris stage of evolution, 485 density, 10-12 , role in, 432, 465 hurricane , 604, 614, dynamics, 289-328 in hurricanes, 628 620, 624 heat transfer globally, 339 radiative forcings, 687 lightning from, 564 gases, 7 radix layer, 700-705 thunderstorms, 481-602 layers, defined, 13, 563, 565 residual layer, 692-696 crawlers (lightning), 567 optics, 833-868 response to heating and frictional drag, 687-705 lightning, 564, 567 physics, 872 roughness length, 677-678, 700-703 apex method (static stability), 139 pressure head, 632 Davenport-Wieringa classification, 700 aphelion, Earth orbit, 28-30 radiation emissions, climate, 795-797 rural, 677-679 precession, 800-801 radiative transfer, 220-226 seasonal variations, 695-696 apparent refraction of light, 861-863 slab model, 697-698 force, 299 science, 205, 877 stable boundary layer (SBL), 692, 696 sunrise and sunset, 33-34, 861-862 sounding, pre thunderstorm, 496-499 depth and e-folding height, 696 temperature, 76-78, 117 spectrum of transmittance, 222-223 smoke dispersion within, 732-734 heat index, 77-78, 117 structure (in the vertical), 11-13 smoke plume rise within, 732-733 humidex, 77-78, 117 window, 796, 811 standard deviations for, 707 wind chill, 76-77 “closed”, 796, 811 strength, 696 appearance of thunderstorms, 482 atmospheric boundary layer (ABL), 13, 68, 687-722 winds, 702-703 applications of thermo diagrams, 127-133 accumulated cooling or heating, 693-694 static stability, 687 applied meteorology, 2 aerosols within, 188 stormy, 691 approach to African Sahara, 611 stress, 700-701, 712-715 airports, 563 airmasses are, 393-396, 691 strength of stable boundary layer, 696 geostrophy, 303-304 air parcels in, 687 structure and evolution, 692 approximate solution, 749 anticyclones, relationship to, 390, 690-692 layers within, 692 approximations to spatial gradients, 754-755 Ball ratio, 698 subgeostrophic winds, 699-700 Aqua satellite, 273 buoyancy velocity, 704 summer, 695-696 AR5 (report from Intergov. Panel on Climate capping inversion, 496-499, 522-525, 687-692 supergeostrophic winds, 699-700 Change), 39, 793-832 constant flux layer, 692 surface layer, 692 Arakawa, Akio, 753 convection: free vs. forced, 704 thickness, 700 NWP grids A - E, 753 convective wind profiles, 700-703 arbitrary vertical cross section (AVCS) radar display, boundary layer (CBL), 109, 649, 692 synoptic forcings, 690-692 242 velocity scales, 704 temperature, 13, 693-698 arc cyclolysis, role in, 432 cumulative heating or cooling, 693-694 catalog & diagram of most arcs, 854-855 daytime (convective), 692 inversion, 690-695 circumhorizon (optical phenomenon), 848-849, accumulated heating, 693-694 mixed-layer temperature, 697-698 855 Deardorff velocity, 69, 703-704 stable-boundary-layer temperature, 696 circumzenith (optical phenomenon), 848-849, defined, 13 temperature-profile evolution, 694-696 854-855 depth estimate from soundings, 143 temperature profiles, 688-698 (arcus) clouds, 169, 482, 562 depth and strength over time, 110, 649 thermal-internal (TIBL), 654-657 coloring, 848-849 during airmass genesis, 394-395 thermals, 648-649 of maximum polarization, 856 depth within an , 690-692 thermo diagrams for, 151, 157-158 tangent, 851-853 depth within a , 319, 690-692 thermodynamic method for ML growth, 697-698 Archimedes, 135, 150 dispersion of smoke within, 723-744 thickness, 13, 300, 649 Arctic neutral and stable ABLs, 732-734 top of, 496-499, 522-525, 689 aerosols and CCN at, 188 unstable ABLs, 735-737 tropospheric constraints, 13, 689-692 airmass diurnal cycle, 687 turbulence, 13, 687-690 code for, 392 drag, 300-301, 699-702 airmass, 393-396 formation, 396 coefficients, 700-701 drag, 300-301 circle, 31 in hurricane, 625 free and forced convection, 704, 710 884 INDEX A, B

isotropy, 707-708 bears’s cage (region in thunderstorm), 495, mean and turbulent parts, 705-706 B 583 transport velocity, 300 B-grid, 753 beaver tail cloud, 483, 492, 494-495 turbulence kinetic energy (TKE), 708-709 background state, mean, 316 Beaufort wind scale number, 635-636 turbulent fluxes and covariances, 711-713 errors, 766 related to tornado intensity, 599 variance and standard deviation, 706-708 backing of wind, due to cold air advection, 349 Beer’s Law, 43, 856 unstable (convective), 648-649, 704, 710 backscatter cross-section, 245 bell curve, Gaussian, 729-730, 875 mixed layer, 692 backward scattering, 219, 857 bending of light (refraction), 833-868 smoke dispersion within, 735-737 backward trajectory, 724 beneficial competition (cloud seeding), 553 smoke plume centerline, 736 in semi-Lagrangian NWP, 761 bent-back front, 414-415 standard deviations for, 707 of pollutant emissions, 724 benzene, 725 static stability, 300, 308 bacteria as ice nuclei, 195 Bergen School of Meteorology, 399 winds in radix layer, 703-705 bad-weather regions (extratropical cyclones), 425- Bergeron, T., 201-202, 399 urban, 678-679 480 Bermuda high, 354-356 vertical velocity at top of, 319-320 local winds modified by terrain, 645 role in steering hurricanes, 607-608 wind, 307-309, 699-705 balance of Bernoulli’s diurnal evolution, 699-700 forces to make winds, 302-314 constant, 669-672 log profile in the neutral surface layer, 700- heat, 64 equation, 559, 669-674 702 globally, 338-339 applications, 672-675 log-linear profile in the stable surface layer, balanced mass and flow fields, 763-765 derivation, 670 700-703 balloons, weather, 134 downbursts and gust fronts, 559 low-level nocturnal jet, 699-700 pilot, 322 downslope winds - Bora and Foehn, 675-677 profile evolution, 699-700 rawinsonde, 134, 322, 496 dynamic vs. static pressure, 672-674 profile in convective radix layer, 699-705 ball for compressible flow, 671-672 shear, 300 lightning, 567 for incompressible flow, 669-671 subgeostrophic, 699 ratio, 698 hurricanes, 626 supergeostrophic, 699-700 bands , 670 wind profile evolution, 699-700 cumuliform cloud, 425-428 limitations, 671 winter, 695-696 radar, 242-243 principles, 669-672 atmospheres (a pressure unit), 7 radiation absorption, 221 reduced gravity in, 670 atomic clock, 51 rain, 401, 604 requirements, 671 attenuation spiral (in hurricanes), 604-605 tornadoes, 578 coefficient in exponential wind profile, 678 Bangladesh vs. hurricanes, 631 venturi effect and gap winds, 674-675 factor in the radar equation, 245-246 banks of clouds, 168 function, 669-672 radar energy, 241 banner clouds, 165, 667 Berra, Yogi, quotations, 5, 132, 228 rain gauges, 210 barbs for wind, on a weather map, 278 beryllium-10, 803 atto (10–18), 870 baroclinic, 343, 749 beta attractor, 790 atmosphere, 343, 349, 359, 749 effect on fixed point, 790 circulation in, 366 lee cyclogenesis, 444 strange, 773-776 Bjerknes circulation theorem for, 366 tornadoes, 586 audibility distance of thunder, 575-576 instability, 371 vorticity tendency, 447-451 aureole, 860 in African easterly jet, causing waves, 611 plane, 369 aurora, 11 vs. barotropic, 749 term, 447-449, 586 Australian Bureau of Meteorology, 607 wave (Rossby), 371-374 Betz author, about the, XIV idealized structure, 374 Albert, 647 automated weather qualitative model, 371 law, 647-648 forecasts (NWP), 745-792 quantitative approach, 372-374 limit, 648 map analysis, 765-767 zones and cyclone self-development, 469-471 bias (mean error; systematic error), 770, 778, 875 station METAR report, 270 strengthening, 469-470 score, 781 autumnal (Fall) equinox, 30-31, 800 baroclinicity, 359 Big Thompson Canyon flash flood, 487, 547-548 availability of water for droplet formation, 186-187 polar jet driven by, 359-360 big whirls have little whirls (eddies), 708 available role in tornado formation, 587 billow clouds, 142, 165 energy, 503-508, 557-558 barogaph, 19, 278 bimetalic strip thermometer, 78 potential energy, 356 barometer, 7, 19, 219 bin size, 646 convective (CAPE), 503-508 aneroid, contra, digital, electronic, mercury, 19 binary downdraft (DCAPE), 557-558 Torricelli (U-tube), 19 bits, 759, 870 supersaturation, 187 barometric event verification, 780-782 average, 502, 705, 726 pressure (see pressure), 7-19, 267, 270, 275 biogeochemical climate-change processes, 810 daily insolation, 40-41, 336, 799-802 tendency, weather map symbols, 278 biological energy budget, global, 797 barotropic, 749 climate change process, 810-812 ensemble, 776 atmosphere, 366, 749 homeostasis & daisyworld, 813-815 speeds, winter, 357-361 circulation in, 366 bits, binary, 759, 870 meridional kinematic heat flux, 338-339, 375, 378 Kelvin’s circulation theorem for, 366 Bjerknes observations, 875 instability, 367-370 circulation theorem, 366 running, 599 easterly waves in African jet caused by, 611 Jacob, 399, 450 total water mixing ratio, 98 Rossby waves caused by, 367-370 Vilhelm, 399, 759 wavelength of wind waves, 634 vs. baroclinic, 749 bkn (broken) cloud cover, 170 winds in global circulation, 330-331 wave, 367-370 blackbody, 36, 39, 794 averaging, 502, 705, 726 barren daisyworld, 815 radiance, 221, 224-225 distance, 706 barrier to ice formation, 194 blades of wind turbines, 647 time, 706 (s), unit of pressure, 7, 870 blank diagrams that you can copy aviation (also see aircraft and airplanes) barycenter, 27 hodograph, 512 boundary layer turbulence, 649 basal face, 842 thermo diagrams, 151-158 runways vs. wind directions, 646-647 base blanket-shaped clouds (see stratus), 162-163 severe weather hazards, 529 cloud height, 93, 130, 162, 278 blessing, 863 Avogadro constant, 879 fog, 177 blizzard, 208-209 AWIPS, 772 of natural logarithms, 879 associated with extratropical cyclones, 425, 434- AWOS (Automated Weather Observing System), 271 rain-free, 483 435 basic blocking of airmass movement by mountains, 397, axes of graphs (defined, and switching of), 3 dimensions, 870 667 axial precession of Earth, 799-801 thunderstorms, 486-487 blow up (of numerical weather forecast), 757, 760 axis of basis, scientific, for weather forecasting, 746-751 blowing snow, weather-map symbol for, 275-276 contraction, 320-321 BATHY code, 269 blue dilation, 320-321, 410 battering of structures by waves, 634-635 color defined (also see optics chapter), 37, 834 tilt of earth, 30, 798-802 be creative, 293 haze, 858 ridges and troughs, 281, 367, 399 be safe, 485, 517, 567, 570, 583-584 jet, 563, 568 azimuth angle, 4-5 beach erosion by ocean waves, 634-635 moon, 805, 858 defined, 2, 4 bead lightning, 567 sky, 857-858 , 354-356 beam, radar, 240 Rayleigh vs. Newton theories, 863 role in steering hurricanes, 607-608 propagation sun, 858 equation, 244 Bohr, Niels, 745 path, 243-245 boiling, 90 width, 240 bolometer, 46 B, C R. STULL • PRACTICAL METEOROLOGY 885 bolt data, 268 and nonlocal conditional instability, 503 from the blue, 567 bugs breaking, 524-527 lightning (see return stroke), 556-567 computer coding, 759 clouds, 165, 666-667 Boltzmann constant, 37, 118, 189, 879 radar observations of, 248-249 convective inhibition (CIN), 522-527 bomb building codes, 772 definition (inhibiting thunderstorms), 496-499, cyclone, 426 bulb, wet or dry, 78, 94-96 522-524 nuclear, 499, 548 bulk strength reduction by jet streak, 526 Bond albedo, 831, 879 heat transfer coefficient, 68, 397-398 traps humid-air fuel for thunderstorms, 503 bookend vortices, 490-491 airmass modification, 397-398 vs. capping inversion, 497 Bora winds vs. katabatic winds, 675-676 moisture transfer coefficient, 109 CAPE (convective available potential energy), bore: Morning Glory, 656 Richardson number 503-508, 530-531, 590 Bosart, 765 dynamic stability, 141-142 downdraft (DCAPE), 530-531, 557-559 Bosnia, bora winds, 675 shear, 522, 530-531 vs. CAPE, 558 boundary thunderstorm, 521-522, 530-531 energy helicity index (EHI), 591-592 airmass, 525-526 bullet shaped ice crystals, 199 hail forecasting, 550-552 drylines, 416, 525 bumpy ride in aircraft, 649, 667 in hurricanes, 609 fronts, 399-415, 525 Bunker’s internal dynamics method, storm motion, Cape Verde Islands, 611 thunderstorm trigger, 525 518-520 capillatus/cap (cumulonimbus), 168, 482 conditions, 731, 756, 816 BUOY code, 269, 271 capped column ice-crystal shapes, 199 currents in oceans, 431 buoy, cycloidal paths of, 312 CAPPI radar displays, 242 boundary-layer (see atmospheric boundary layer, buoyancy, 62, 135-136 capping temperature inversion, 496-499, 522-527, 687- ABL), 13, 687-722 definition, 135-136, 316-317 698 gradient wind, 309-311 generated turbulence, 709 Capricorn, 31 in hurricanes, 609, 618-619 length scale, 733 carbon in tropical depression, 613 negative (downward), 554-563 14 isotope, 803 growth, 689 neutral, 135 cycle, global, 812 parameterizations in NWP models, 751 on thermo diagram, 135 dioxide (also see CO2), 7, 805 pre-storm, 496, 499-503 positive (upward; also see CAPE), 503-508 effervescence from oceans, 812 pumping, 319-320, 432 pressure-perturbation, 555 greenhouse gas, 811-812 cyclolysis, role in, 432, 465 role in katabatic wind, 653 Keeling (hockey stick) curve, 812 in hurricanes, 628 velocity, 68-69, 110, 300, 704 film hygrometer, 111 thermal internal (TIBL), 654-657 scale, 68-69, 110, 300, 394-395, 704 monoxide, CO, 7, 725 total water, 99 virtual potential temperature, 62 cardiopulmonary resuscitation (CPR), 567, 571 urban, 678-679 waves, 666-668, 710 cargo-cult science, 167 wind, 307-309 thunderstorm triggering, 526 Carnot cycle, 624-625 profilers, 259 buoyant Carnot, S., 89 tunnels, 689 consumption of turbulence, 709 Cartesian coordinate system, 2, 293 bounded weak echo region (BWER), 552-553 force, 135-136, 316-317, 554 framework, 293 bounds on climate change, 811 along mountain slope, 650-651 cartography, 4 Boussinesq approximation, 316 in neutral and stable regions, 135-136 cas (castellanus), 168 bow echo, 490-491, 494, 516 of rain laden air, 554-563 cascade of vertical vorticity, 586 Bowen ratio, 74-76 pressure-couplets caused by, 341 case study measurement, 75 forcings, 135, 315-317, 341, 403, 496-499, 503-508, cyclone, 433-443, 448-456, 459-463, 466, 745, 768- method of estimating surface fluxes, 75 554-559, 649-653 770, 776 bows (rainbows, moon bows, supernumerary), 837- production of turbulence, 709 forecast, 745, 768-770, 776 841, 860-861 thermals, 648-649 thermal wind, 348-349 box turbulence, 704 thunderstorm, 500-501, 506-508, 522-525, 528-529, and whisker diagram (statistics), 539 Burgers-Rott , 599 532, 551-552, 558, 568, 590-591 counting (fractal dimension), 172 burning the air (by lightning), 567 castellanus clouds, 162, 164, 168 Bradbury, Ray, 775 bursticane, 602 castle-like mirages: Fata Morgana, 862-863 branched star ice crystal shapes, 199 bursts of rain, 547 CAT = clear air turbulence, 142, 165 breakdown butterfly, Lorenz attractor, 774-775 L band radar to view, 242 bubble in tornado, 592-593 Byron, Lord, 805 categorical event verification, 780-782 of zonal flow, 367-376 categories of potential for lightning, 566, 880 clouds, 168-169 breaking the cap of thunderstorm inhibition, 522- hurricane intensities, 605-607 527 tornado intensities, 579-580 breaking waves in the atmosphere (K-H waves), 142, C cats and dogs, raining, 206 165 C and C++ programming languages, trig conven- cavity of reverse flow, 667 fluctus clouds, 169 tions, 3 cauliflower-shaped clouds (see cumulus), 161-162 breath, condensation within, 160 C band radar, 242 CB (cumulonimbus, thunderstorm), 481 breeze, 635-636 C, degrees Celsius or centigrade, 7 cc (cirrocumulus clouds), 168 lake, 654-657 C-grid, 753 CCD, 46 sea, 654-657 cadmium iodide, 195-196 CCN (see cloud condensation nuclei), 188-189 inland, 654 cal (calvus), 168 CDP ( Damage Potential), 607 urban, 679 Calabrian age, 799 CDT, Central daylight time (Americas), 5 briefing, weather, 765 calculation of ceiling, 170 Brier skill score, 782, 785 weather (numerical), 745-792 change criterion for SPECI, 270 bright band, 248 secondary variables, 771-772 celestial sphere, 834, 854 brightness temperature, 211, 221-224 calculus, 11, 16, 18, 293, 872 cell British Commonwealth (thermo diagrams used by), calibrated probabilistic forecasts, 777 closed-cell clouds, 167 121 calibration errors, 875 direct and indirect circulation, 377 broken (bkn) cloud cover, 170, 279 California (advection) fog, 173-175 Ferrel, 332-333, 357, 377 brown cloud, 857-858 calm winds, weather-map symbol for, 278 grid, 750-758 Brunt-Väisälä frequency, 136-137, 658-659, 666-668 calvus (cumulonimbus), 168, 482 Hadley, 329, 332-333, 350-351, 377-378 use in baroclinic wave equation, 372-373 camera filters open-cell clouds, 167 use in group velocity for waves, 658-659 haze, 858 polar, 329, 332-333, 352, 378 use in mountain lee waves, 666-668 polarizing, 857 solar, 46 use in Rossby radius of deformation, 344 Canada/Canadian thunderstorm, 484-487, 492-495 use in smoke plume rise, 733-734 air quality standards, 725 Celsius, degrees, unit of temperature, 7, 870 bubble, updraft, 482 geography & province abbreviations, 431 center budget Hurricane Centre, 617, 638 of mass equation(s), 713, 746-747 hurricanes, 617 hodograph, for normal storm motion, 516- energy, global annual mean, 797 lightning, 566 517 heat , 57-76, 713, 746-747 Vancouver, British Columbia, 32-33, 472, 646-647 pollutant, 729, 736 mass, 746-747 Cancer, Tropic of, 31 Storm Prediction Center (SPC), 532 momentum, 746-747 candela, 870 centered finite difference scheme, 755-757 net heat, 72-73 canopy flows, 677-679 spatial (2nd & 4th orders), 755 radiation, 42, 44-45 forest or plant, 677-678 temporal (leapfrog), 757 global annual mean, 797 urban or city, 678-679 centerline height, 723, 729, 736 surface heat, 73-76 winds at canopy top, 678 centi (10–2), 870 water, 99-111, 746-747 canyon, urban, 678 centigrade = celsius, 7 BUFR = binary universal form for representation of cap central 886 INDEX C

dense overcast (CDO), 614 sea-breeze, 654-657 astronomical influences, 797-803 limit theorem, 184 secondary, 412, 455-456 reference state, 794 European time (CET), 5 thermal (hydrostatic), 341-342, 648-657 sea-surface temperature variations, 818-820 time zone (Americas), 5 thermally direct, 351, 412 sensitivity, 810-812 centrifugal force, 296, 301 three-band general, 329, 376-378 definition, 810-812 explanation of Coriolis force, 298-299 through hurricane, 620-625 factor & usage, 812 in hurricane, 617-618 transverse frontal, 412 magnitudes & processes, 812 sign coefficient, 296 urban, 679 southern oscillation, 818-820 centripetal force, 296, 301 vertical, 332-333, 377-378 variability related to BLG wind, 309-311 vorticity, relationship to, 366 astronomical influences, 797-803 related to cyclostrophic wind, 311-312 Walker, 820 continent movement, 804 related to gradient wind, 304-307 circumhorizon arc, 848-849, 855 tectonic influences, 804-805 related to hurricanes, 617-619 circumpolar trough, 432 volcanism, 804-805 related to inertial wind, 312 circumscribed halo, 851, 853-855 water-vapor and cloud feedbacks, 810-811 CET (Central European Time), 5 circumzenith arc , 848-849, 854-855 climatic precession, 799-802 CFC-12 (freon; halocarbons), 796, 811-812 cirro prefix, 163 climatological average, 330 CFL criterion for numerical stability, 760-761 cirrocumulus, 162-163, 168 highs, 354-356 channel(ed) satellite images of, 234 lows, 354-356 flow, open-hydraulics, 657-661 cirroform clouds, weather-map symbol for, 276 pressure patterns globally, 354-355 of lightning, 563 cirrostratus, 162-163, 168 storm () tracks, 430-431 winds, 664 satellite images of, 234 vertical cross section of atmosphere, 359 channeling of airmasses by mountains, 397 cirrus, 162-163, 168 winds near tropopause, 358 channels on satellites, 222-223, 230 satellite images of, 234 climatology/climatologies of chaos, 1, 773 citing the work of others (giving credit where due), hurricanes, , tropical cyclones, 630-631 theory & nonlinear dynamics, 773-776 24 lightning, 564 characteristic soundings for clouds, 162, 496-499, citizen scientist, 738 numerical weather forecasts, 772, 776 503-508 city (urban) canopy, 678-679 reference for verification, 780 charge, electric, 564 temperature excess relative to rural, 679 CLINP code, 269 transfer to/from ice crystals, 565 civil CLISA code, 269 charge-coupled devics (CCDs), 46 defense sirens for storm warning, 529 clock charging rate & zone of thunderstorm, 564-566 twilight, 33-34 24 hour, 6 Charney, Jule, 749, 759 Clapeyron, B.-P.-E., 89 mechanical & sundial, 34 charts, weather classes of stability, 138-141 time correction (eq. of time), 34 analysis methods, 274-281 classic supercell, 482-483, 486, 492-494, 549 clockwise, 2 case-study examples, 433-466 wind statistics for, 585 closed multi-field, utility of, 443 classification of cellular convection, 167 chaser, storm, 583 clouds, 168-169 system of equations, 714 chasing , 484, 583 snow grains, 199 closure, turbulence core punching, 583 thunderstorm types, 486 K-theory & other local, 714-716 safety, 485, 517, 567, 570, 583-584 winds, 302, 314 mathematical, 714 chemical energy, 54 Clausius, R., 89 parameterization types, 714-716 chemicals & chemical symbols, 7, 725 Clausius-Clapeyron equation, 88-92 problem, 713-714 equilibria, 132 as affects mixing and saturation, 160-161 transilient theory & other nonlocal, 716 gases/pollutants in the atmosphere, 7, 725 clay (kaolinite), 195 cloud(s), 159-184 chill, wind, 76-77 Clean Air Act, 7 accessory, 168-169 chilled mirror (dew-point) hygrometer, 97, 111 clear active, 162 Chinooks , 676-677 air scans; returns on radar, 249 advective, 94, 164 Churchill, Winston, 530 air turbulence (CAT), 142, 165 airmass, 393-397 ci (cirrus clouds), 168 L band radar to view, 242 altocumulus, 134, 162-163, 168 CIN (convective inhibition, of thunderstorms), sky, 170, 279 castellanus, 164-165 522-525, 530-531, 590 CLIMAT codes (SHIP, TEMP, TEMP SHIP), 269 altostratus, 134, 162-164, 168 cap on convection, 524 climate, 793-832 anabatic cumulus, 162, 649-650 mean-layer, 524 30-year average, 354, 355, 358, 816 anthropogenic, 166 cinnamon roll shape of occluding cyclones, 472 abrupt-change causes, 810 anvil (incus), 169, 482-484, 604, 614, 620, 624 Circles anomaly, 818-819, 821 debris, 485 Arctic and Antarctic, 31 warm (ENSO and PDO), 818-820 arc/arcus or shelf, 169, 482, 562 of light in the sky (see optics), 833-868 anthropogenic vs. natural effects, 812 arrangement, 169 circular Arctic Oscillation (AO), 818-819, 824 aspect ratio of, 485 frequency, 36 astronomical influences, 797-803 asperitas, 169 orbits, 27 atmospheric window, 796, 811 associated with thunderstorms, 482-484 symmetry, 572 averaging time, 817 atlas, 168 circulation change banks, 168 absolute, 366 abrupt, 810 banner, 165, 667 ageostrophic, 410, 455-456 bounds, 811 base along-valley, 653-654 effects of pollutants on, 724 detrainment instability, 484 atmospheric and oceanic, 339, 378 gradual, 810 estimation of height, 93, 130, 162 baroclinic & barotropic atmospheres, in, 366 natural vs. human-caused, 812 for descending air, 130 Bjerknes theorem, 366 classification (Köppen), 816-817 on thermo diagram, 130, 134, 496-499 cells clouds, and condensation, 810-811 rain-free, 483 direct vertical, 351 codes & criteria, 816-817 height, weather-map symbols for, 277-278 Ferrel, 333, 357 daisyworld, 813-815 thunderstorm, 496-506 Hadley, 350-351 definition, 816-817 beaver tail, 483 indirect vertical, 333, 357 El Niño - Southern Oscillation (ENSO), 818-820 billow, 142, 165 polar, 352 feedbacks, 806-812 broken, 170 cross global climate models (GCMs), 815-816 brown, 857-858 frontal, 412 gradual-change causes, 810 buoyancy within, 159 valley, 649-653 greenhouse effect, 795-796 bursts, 547 defined, 365-366, 377 ice-albedo feedback, 808-812 calvus, 168 direct, 351, 376-377, 456 IPCC (Intergovernmental Panel on Climate cap, 165 driven by pressure perturbations, 340-341 Change), 812 capillatus, 168 general, 329-388 Köppen classification, 816-817 castellanus, 162, 164-165, 168 global, 329-388 La Niña, 818-820 categories, 168-169 explaining, 350-356 Madden-Julian oscillation (MJO), 818-819, 824 cauda, 169 Hadley, 329, 332-333, 350-351 Milankovitch theory, 797-803 cavum, 169 horizontal, 365-366 natural processes, 793-832 ceiling, 170 hurricane, 620-625 normal, 818 thunderstorm, 484-485 indirect, 456 North Atlantic oscillation (NAO), 818-819, 824 closed, 167 Kelvin’s theorem, 366 of NWP model, 776 open, 167 lake breeze, 654-657 orbital effects, 797-803 central dense overcast (CDO), 614 monsoon, 333-334, 356 oscillations, 818-824 change criterion for SPECI, 270 mountain/valley, 649-654, 660-670, 675-677 Pacific decadal oscillation (PDO), 818-820 cirro prefix, 163 relative, 366 present, 816-817 cirrocumulus, 162-163, 168 Sawyer-Eliassen, 412 radiative equilibrium, 793-797 cirrostratus, 162-163, 168 C R. STULL • PRACTICAL METEOROLOGY 887

cirrus, 162-163, 168, 485 intortus, 169 symbols on weather maps, 168 classification, 168-169 K-H wave, 142, 165 tail, 483 clear, 170 lacunosus, 169 thermo diagram (detection using), 134 climate feedbacks, 810-811 Lagrangian heat budget within, 159 thickness, 161-162 cold lapse rate inside, 101-106 thunderstorm, 481-602 frontal cumuliform clouds, 162, 400, 404 layers, 168 -to-air lightning (air discharge; CA), 563 process of precipitation formation, 201-202 as reported in METAR, 270 -to-cloud lightning (CC), 563 colors in, 856-861 lee-wave, 165, 666-668 -to-ground lightning (CG), 563 condensation nuclei (CCN), 185, 188-189 lenticular/lenticularis, 165, 168, 666-668, 684-685 top, 162 airmass characteristics of, 391 optical phenomena, 859-860 IR cooling at, 484, 488-489 density equation, 189 lines, 167 track winds, 321-322 giant, 206 mammatus/mamma, 169, 484 trade cumulus, 351 Junge distribution of, 189 man-made, 166 translucidus, 169 number density, 188-189 mesoscale cellular convection, 167 transparency, 169 sources, 188 mesoscale convective complex, 486, 491 triggering mechanisms congestus, 162, 168 mediocris, 161-162, 168 cold fronts, 162 , 160, 166 , 483 mountains, 162 climate change effects, 812 mesoscale cellular convection (MCC), 167 tuba, 169 convective, 93, 161-162 METAR, 270 turbulence and mixing, 132, 165-166 cooling in, 101-106 meteors, 168-169 types, 168-169 coverage/cover fraction, 170 microphysics, 185-218 uncinus, 168 not measured, 170 parameterization in NWP models, 751 undulatus, 169 parameterization in NWP models, 751 (in) midlatitude cyclones, 425-428, 472 urban, 162 total, weather map symbol, 279 morphology, 168 varieties, 168-169 vs. PG turbulence type, 728 mother, 168-169 veils, 168 creation processes, 159-161 -of-pearl, 166 velum, 169 cumuliform, 93, 161-162, 170, 482-484 mountain-related (orographic), 162, 165-168, 649- vertebratus, 169 cumulonimbus (cb), 161-162, 168, 481-602 650, 676-677 , 169 cumulus (cu), 161-162, 168 mountain-wave, 165 volutus, 168 anabatic, 162 movement, 483 wall, 483, 581-583 castellanus, 164-165 murus, 169 warm frontal, stratiform clouds, 162-164, 401, congestus (cu con), 161-162, 483 nacreous, 166 404 fair-weather (humilis), 161, 498 names, 161-169 wave (see lenticular), 165, 168, 666-668, 684-685, fractus (), 165-166, 483 NAT, 166 859 humilis, 161, 498 nebulosis, 168 weather map symbols for, 168, 277 mediocris (cu med), 161-162, 483 nimbostratus, 162-163, 168 white color of, 857 towering (tcu), 161-162, 483 noctilucent, 166 WMO , 168 decks, 164 obscured, 170 cloudiness destabilization and cloud formation, 162 observation from satellite, 220 airmass characteristics of, 391 determination from soundings, 164 occluded frontal clouds, 413 constant (isoneph), 18 development, 161-166 opacus, 169 feedback factor for climate change, 810 active-cumuliform, 161-162 organization, 167 related to albedo, 44, 811 passive-stratiform, 162-164 orographic, 162, 165-168, 649-650, 676-677 cloud-radiation interaction, 131-132 stratocumulus, 164 overcast, 170 clusters of ice crystals, 199 dimensions, 168 pannus, 169 CO, carbon monoxide, 7, 725 dome (overshooting thunderstorm top), 483 passive, 163 CO2, carbon dioxide, 7 droplets, 159, 185-218 perlucidus, 169 biological climate feedback, 810-812 fall velocities, 159, 202 photographic tips, 180, 484 doubling, 812 distance between, 194 physics thunder parameter (CPTP), 530 fossil fuels vs. global cycle, 812 scattering of light by, 856-859 , 165, 169, 483 greenhouse gas, 811-812 typical sizes, 185 polar, 166 Keeling (hockey stick) curve, 812 duplicatus, 169 mesospheric (PMC), 166 ocean, feedback for climate, 810-812 dust (), 562 stratospheric (PSC), 166 effervescence, 812 electrification, 564-566 praecipitatio, 169 sequestered, 812 eyewall, 604-605, 618-620, 624-629, 637 radiatus, 169 transpired and release during wild fires, 812 feedbacks for climate, 810-811 rain, 482-483, 486 coagulation, 188 few, 170 rain-free base of, 483 coalescence, 202-207 fibratus, 168 roll, 169 efficiency, 204-205 filaments, 168 rotor, 165, 667 coarse flanking line, 483 sand, 562 mode CCN formation, 188 floccus, 168 satellite images of, 232-234 resolution NWP & GCMs, 752, 815 fluctus, 169 saturation within, 159-161 coastal flumen, 169 scarf, 165 breezes, 654-657 foehn wall, 676-677 scattered, 170 fogs (advection fog), 173-175 fog, 159 scattering of light from, 856-858 hazards of hurricanes, 634 forecasts scud (cumulus fractus), 483 jets, 664-665 formation, 98, 159-161 seeding, 195-196, 218, 553-554 waves and surf, 634-636 in anabatic flows, 162 creating a hole (cavum) in layer clouds, 169 winds, 654-657, 661-665 in cold air advection, 162 shapes, 171 coastally trapped low-level barrier jets, 664-665 orographic, 168 sheets, 168 cockroach, 151, 815 via cooling, 159 shelf, 482, 562 CODAR code, 269 via adding moisture, 160 shield CODATA, 876, 879 via mixing, 160-161 from hurricanes, 604 codes for forms, 168 from thunderstorms, 488 airmasses, 391-392 fractus, 165-166, 168, 483 warm-frontal, 425-428 building, 772 -free air around thunderstorms, 546 sizes, 170 weather reports, 268-273 frontal snow-banner, 165 coefficient cold front and cumuliform, 162, 400, 404 species, 168 drag, 700-701 occluded fronts, 413 spissatus, 168 extinction, 43 warm front and stratiform, 162-164, 401, 404 standing lenticular, 165, 666-668, 684-685 cold fumulus, 166 optical phenomena, 859-860 air funnel (also see tornado), 169, 483 static stability within, 159 advection and backing of wind, 349 genera, 168 stratiform/stratiformis, 94, 162-164, 168 advection and cloud formation, 162 glaciated, 485 stratocumulus, 164, 168 aloft in pre-storm environment, 496, 503 haboob, 562 stratus, 162-163, 168 pool from thunderstorms, 488-489 hat, 165 streets, 167 pool at night, 653 hole in a cloud layer (cavum), 169 striations, 483 sector, 425-428 horizontal roll vortices, 167 structure, 168 airmass, 392 humilis, 161, 168 STS clouds, 166 depth, 404-406 hurricane, 603-644 subcategories, 168-169 genesis, 393-397 ice-crystal, in arctic airmasses, 393-397 supercell, 482-483 cloud identification, 161-169 supplementary features, 168-169 precipitation aggregation, 202, 205 incus, 169 surface-turbulence related, 165-166 process of precipitation formation, 201-202, 888 INDEX C

205-206, 546 amount in rising air parcels, 130 climate change effects, 812 seeding, 196 convective condensation level (CCL), 526-527 controlling the weather, 218 tops in thunderstorms, 206 freezing, 195 convection core systems, 426, 622 funnel of tornado, 581-583 deep (i.e., thunderstorms), 481-601 vs. warm core, 622 energy in hurricanes, 620 parameterizations in NWP, 751 frontogenesis, 281, 399 latent heat of, 56 definition, 66, 649 frontolysis, 281, 399 lifting condensation level (LCL), 93-94, 496-506 forced vs. free, 704, 710, 727 front, 399-404 nuclei (see also CCN), 188 free, 704, 710 aloft, map symbol for, 281, 399 on to snow, 110 smoke dispersion within, 735-737 cumuliform clouds, 162, 400, 425-428 role in frontal strengthening, 411 level of free (LFC), 496-506 definition, 404 role in self development of cyclone, 465-471 limit of (LOC), 498 deformation behind, 470-471 trail (), 160, 166 moist (i.e., thunderstorms), 496, 649 descent and diffluence behind, 433, 470-471 conditional instability, 140-141 organized, in tropical disturbance, 613 depth, 405 nonlocal, in hurricane environment, 609 parameterizations in NWP models, 751 extratropical cyclone, attached to, 425-428 nonlocal, in thunderstorm environment, 140, penetrative, 508 horizontal structure, 400 496-499, 503-508 convective occlusion, 413 conditionally unstable, 140-141 adjustment, moist, 70 propagation, found using Q-vectors, 470-471 conditions favoring thunderstorms, 496-499 available potential energy (CAPE), 503-508, 530- radar observations of, 248-249 conduction, 67-69 531 thunderstorms along, 400 contribution to airmass genesis, 393 boundary layer, 68, 109-110 trigger for hurricanes, 612-613 contribution to frontolysis, 411 circulations, 134-139, 161-162, 332, 341-342, 350- trigger for thunderstorms, 525 from cloud droplets, 185, 197 351, 357, 376-378, 481-544, 648-657, 704 weather map symbols for, 281 (and) turbulence on windy days, 68 clouds (including thunderstorms), 93, 138, 161- high-pressure centers, 341-342 conductive heat flux, 67-69 162, 481-601 katafront, 404 at surface, 73-76 formation regions, 162 mode rainfall estimates, 257 conductivity, molecular, 67-68, 880 condensation level (CCL), 526-527 sector of extratropical cyclones, 425-428 cone shaped tornadoes, 577 conditions for thunderstorm formation, 68, 496- vs. warm core cyclones, 622 confidence in NWP forecasts, 776 499 collection, 202-207 confluence, 409-410 inhibition (CIN), 522-525, 530-531 and aggregation processes, 204-205 frontogenesis, 409-410 instability (nonlocal conditional), 498, 503-508 efficiency, 205 conformal map projections, 748 mixed layer, 648-649, 692, 695, 697-698 collision efficiency, 204 congestus/con, cumulus, 161-162, 168, 483 airmass, 393-396 collision and collection, 202-207 pileus clouds created by, 165 depth, 649, 695, 697-698 of hydrometeors, 185, 202-207 coning, pollutant plume, 710, 727 humid. Role in thunderstorms., 497-501 droplet size distributions, 207 consequences of doing science, 218 smoke dispersion within, 735-737 processes, 202-207 conservation of winds in radix layer, 703-705 terminal velocity of droplets, 202-204 angular momentum, 360-361 mixing, 301 colors breakdown of, 361 outlooks, 528-530 angles of 22 degree halo, 845 energy along a streamline, 671-672 radix layer, 703-705 defined, 37, 834-835, 862 heat, 1, 59, 64, 746-747 temperature, 526-527 dispersion of, 834, 862 isentropic potential vorticity, 364-365 towers, hot, 644 Newton’s work on, 862 mass, 317-320, 660, 746-747 transport coefficient, 68, 110 of halos and arcs, 845-851 momentum, 392-393, 746-747 for heat, 68, 110 of rainbow, 838-840 potential vorticity, 363-364, 445 for moisture, 110 of sky, 857-858 total water, 1, 107, 746-747 turbulence, 508, 527-530, 704 of sunset, 858 conservative tracers, 731 generation, 706 scattered vs. particle diameter, 858 conserved variable, 61, 104 velocity scales, 68-69, 704 wavelengths of, 37, 834-835, 862 constant vortex, mesoscale, 492 Columbus, Christopher, 607 altitude plan position indicator (radar), 242 winds in boundary layer, 703-705 column flux layer, 692 conventions - mathematical and meteorological, 2 ice crystals, 198-199, 842 gases in the atmosphere, 7 convergence, 318-321 hollow, 198-199, 866 height map (such as mean-sea level), 436 evolution vs. cyclone evolution, 467 optics caused by, 842-855 case-study cyclone examples, 434, 438 line, 281, 399 of air in closed cylinder, 55, 463-465 vs. isobaric map, 290-291, 436 of air at bottom of cyclones (lows), 309, 331, 691 combined parameters and conversion factors, 880 potential temperature map, 437 of air at top of anticyclones (highs), 391 commercial aircraft, 563 potential vorticity map, 437 of air in certain jet streak quadrants, 454-456 compass direction, 2, 646 pressure map, 436 of air in easterly waves, 612 communicating NWP forecasts, 772 pressure difference (giving thickness charts), of mass, 318-321, 340-341 complete thermo diagrams, 121, 151-158 436 of Q-vectors, 460-462, 469-471 complexity of the atmosphere, 1 solar (total solar irradiance), 39 radar observations of, 252-253 component angles of refraction geometry, 833-836 von Kármán, 677, 701 zone components of the atmosphere, 7 constants and conversion factors, 879-880 intertropical (ITCZ), 330-332 composite parameter, for supercell, 591 Earth, 879 Olympic Mtn. & Puget Sound, 472 composition of atmosphere, 7 math, 879 conversion compressible flow, 671-672 universal, 879 constants and conversion factors, 879-880 adiabatic, 671-672 constantan, 78 factors and combined parameters, 880 isothermal, 671 constituents (gases) in the atmosphere, 7 of pollutant concentration units, 724 numerical weather prediction model for, 747 constructive interference, 859-861 of units, 871 compression, 8 contact freezing, 194-195 of wind components, 3 of NWP output into databases & climatologies, continental conveyor belt of warm air, 433 772 airmass code, 392 cooking computational arctic airmasses, 396 boiling temperature vs altitude, 90, 115 evolution, 680 polar (cP) airmass, 392 data, 826 natural selection, 680 genesis, 393-397 cooling computer scale circulations (monsoons), 333-334 accumulated in boundary layer, 693 Amdahl’s Law, 763 continent(s) evaporative, in downbursts, 556 blowing up, 757, 760 aerosols and CCN over, 188, 194 process to make clouds, 159 chips, 752 movement, 804 tower clouds, 166 crash, 757 ocean circulations (monsoons), 333-334, 356 coordinate system, 2 ENIAC, 749, 759 super, 804 aligned with mean wind, 727 Moore’s Law, 752 contingency table, 780 alternative profilers, 763 continuity, 317-318 horizontal, 747 speed-up, 763 effects, 340-341 vertical, 746 vs. human contributions to forecasts, 772 downburst & gust fronts, 561-562 Cartesian (rectangular), 2 computerized (numerical) weather forecasts, 745- driving vertical velocity, 452-456 cylindrical, 2, 627 792 equation, 317-318 eta, 746 concentration, 724-725 flux form, 714 hybrid, 746 of pollutant, 725 sign convention, 320 map-projection, 747-748 crosswind-integrated, 735-737 pressure perturbations related to, 340-341 polar, 2 Gaussian distribution, 729-730, 734, 737 continuous variables, verification of, 777-780 stererographic, 747-748 of pollutant downwind, 724, contours, 17, 121, 151 sigma, 746 units for pollution, 724 contraction, axis of, 320-321 spherical, 747 condensation, 56, 88 contrails (condensation trails), 160, 166 terrain-following, 746, 753 C R. STULL • PRACTICAL METEOROLOGY 889

Coordinated Universal Time (UTC), 5, 268 tilt with altitude, 668 curvature , 375 co-polar correlation coefficient, 256-257 Cretaceous- Earth’s, 244 copper-constantan thermocouple, 78 Paleogene extinction event, 805 effect, 189-192 core Tertiary (KT) extinction event, 805 jet stream, driving updrafts and cyclogenesis, cold, 426, 622 CREX = character form for the representation of 453 of cyclone, 426. 622 data, 268 Laplacian, as a measure of, 450 of hurricane, 604, 614, 618-625 crimson sunset skies, 858 of a line, 450 of jet stream, 357-361 critical radius of light ray, 861 of tornado, 577-578 angle, 837 Rossby number, 306 pressure deficit in evaluation exercises explained, 22 Rossby wave, 375 hurricane, 621-624, 626, 633 flows, 659 terms in equations of motion, 747 tornado, 577-578 Froude number, 659 vorticity, 362 punching, 583 radius, 192 cut warm, 426, 614, 621-622 derivation, 193 in wind speed for turbines, 648 vs. cold, 622 Richardson number, 142, 880 out wind speed for turbines, 648 Coriolis force, 297-299, 301 success index, 781 Cv or Cvd, 55, 880 acting on supersaturation, 192 cyan color defined (also see optics chapter), 37 Antarctic winds, 652 swirl ratio, 593 cycle, global carbon, 812 katabatic winds, 652-653 Croatia, bora winds, 675 cyclogenesis, 426-433 as a component of centrifugal force, 298-299 crop attributes, 446 derivation of equations for, 299 canopy flows/winds, 677-678 characterized by, 426, 446 direction, 297 damage from hail, 549 sea-level pressure decrease, 463-467 explanation of, 298-299, 301 cross upward motion increase, 451-462 factor, 879 equatorial flow cyclonic vorticity increase, 446-450 in gap winds, 662-664 in Hadley cell, 332-333 evolution, 467 in hurricane, 609, 617-619 in monsoon circulations, 356 explosive, 426 in 3D, 297 frontal circulation, 412 favored regions, 426, 431-431, 450, 456 contributing to wind, 302 jet-stream flow, 415 feedbacks, favoring self-development, 468-471 boundary layer, 307 isobaric flow, 307-311, 314, 318-320, 454, 691 hurricane, 608-615 boundary-layer gradient, 309 product vector operator, 299 lee side, 430-431, 443-446 geostrophic, 302 section in isentropic potential vorticity conservation, gradient, 304 baroclinic atmosphere, 373 364-365 inertial, 312 extinction, 43 potential vorticity conservation, 364-365, magnitude, 297-299, 301 fronts, 403-416 445 near equator, 297 global circulation cells, 332 omega equation, 456-462 on objects moving east/west, 298-299 hurricane, 605, 618-624, 629 Q-vectors, 460-462 on objects moving north/south, 299 jet streams, 357 rapid, 426 role in cyclogenesis, 426, 443-450, 609 valley circulation, 649-653 self-development, 468-471 sign convention, 297 wind Sutcliffe development theorem, 456 vertical component, 297 direction definition (i.e., lateral), 727 Trenberth omega equation, 458 Coriolis, Gaspar Gustave, 298 integrated concentration, 735-737 tilt of trough with altitude, role of, 432 Coriolis parameter, 297 crystal (see ice crystal) cycloidal paths of rate of change (beta) with latitude, 297, 369, 879 liquid-crystal thermometer, 78 damage from multi-vortex tornadoes, 593 corkscrew (helical) motion, 587-592 cs (cirrostratus clouds), 168 drifting buoys, 312 corollaries CST, Central standard time (Americas), 5 cyclolysis, 426-433 numerical weather prediction, 756, 758 cu (cumulus clouds), 168 evolution, 467 satellite sounding retrieval, 235-239 cubed sphere grid for NWP, 752 cyclone corona, 858-860 cubic ice (Ic), 198 atmospheric boundary layer within, 690-692 clouds that cause, 163, 667, 859 cumulative bomb, 426 igneous meteors, 205 daytime heating, 693-694 Catarina, 631 vs. halos, 860 seasonal differences, 695 case study, 433-443 correct negative or correct rejection, 780 nighttime cooling, 693 characteristics, 426-433 correction of temperature for dynamic warming, seasonal differences, 695 cold vs. warm core, 622 673 probabilities, 777 convergence of horizontal winds, 691 correlation coefficient, 711, 779 cumuliform clouds damage potential, 607 anomaly, 779-780 along cold fronts, 425-428 deepening, 463 cosine law of radiation (see sine law), 40 altitude of bases, 93 evolution, 427-429 cosmic rays, 565 formed by adiabatic cooling in updrafts, 160 filling, 463 cost, 780 formed by turbulence near surface, 165-166 glyphs (symbols) on weather maps, 426 function, 766-767 typical sizes, 170 graveyard, 431, 472 loss cumulonimbus (see thunderstorm), 161-162, 168, 481- landfalling, at Pacific Northwest coast, 472 decision model, 784-785 602 lifetime, 431 ratio, 785 calvus, 482 propagation and self-development, 469 Cotopaxi volcanic eruption, 805 capillatus, 482 self-development, 468-471 cotton-ball shaped clouds (see cumulus), 161-162 cumulus, 161-162, 168 spin-up, 446-451 coulombs, C, unit of electric charge, 7, 564, 870 anabatic, 162, 649-650 tracks and propagation, 425-426, 430, 469 counter-clockwise, 2 castellanus, 164-165 Q-vectors, 469-471 counter-rotating , 490-491, 587 congestus (cu con), 161-162, 483 warm vs. cold core, 622 coupled equations in math, 393, 747 triggering pileus clouds, 165 cyclone types/names coupled heat and moisture budgets, 108 fair-weather, 161, 498 comparison of, 425-426 couplet fractus, 165-166, 483 cyclones (tropical or extratropical), 425-426 wind, 253, 561 frontal, 400, 404, 413 extratropical cyclones (lows), 425-480 pressure, 340-341 humilis, 161, 498 hurricanes, 603-644 Courant mediocris (cu med), 161-162, 483 low-pressure centers (see extratrop. cyclones), condition, 760 mixing caused by, 301 425-480 number, 758 stage of thunderstorm evolution, 485 lows (see extratropical cyclones chapter), 331, Friedrichs-Lewy (CFL) stability criterion, 760- towering (tcu), 483 425-480 761 trade, 351 mesocyclones (see thunderstorm chapters), 481- courses on meteorology/atmospheric science, 863 weather-map symbols for, 277 602 covariance, 711-713, 821 cup midlatitude cyclones (see extratrop. cyclones), matrix, 821-822 anemometer, 321 425-480 coverage of clouds, total, 279 shaped ice crystals, 199 polar cyclones (see extratrop. cyclones chap.), Cp vs. Cv, 55 cupric sulfide, 195-196 425-480 CPR (cardiopulmonary resuscitation), 567, 571, 638 current storm systems (see extratrop. cyclones chap.), crash density, 565, 655-656 425-480 aircraft, due to bad weather, 563 direct electric, 564 tropical cyclones (see hurricane chapter), 603- computer, 757 units, 564 644 CRC Handbook of Chemistry and Physics, 879 gravity, 655-656 typhoons (see hurricane chapter), 603-644 Creative Commons License, II induced by lightning, 570 cyclonic creativity in lightning, 564, 568-569 rotation direction of most tornadoes, 578, 586 engineering, 288 ocean, 339, 378, 431, 610, 701 vorticity, 446-450 science, 293 , 616 spin-up, 446-450, 586-587 crests of waves, 658, 668 Labrador, 616 cyclonic winds, 306-307, 331 890 INDEX C, D

convergence in the boundary layer, 309, 691 deci (10–1), 870 destructive interference, 859-861 definition, 425 decibels, 246-247 detection networks, lightning, 568-569 cyclostrophic balance, 311-312, 578 decision model, cost/loss, 784-785 deterministic forecasts, 777, 816, 818 cyclostrophic wind, 311-312 decks of clouds, 164 detrainment of air, 57, 484 in hurricane, 609, 618 declination angle, solar, 30-31 instability at cloud base, 484 in tornadoes and , 311, 578 decoding a METAR or SPECI, 270-279 development cylindrical decreasing, weather-map symbol for, 276 clouds, 161-166 coordinates - defined, 3 deductive reasoning, 107-109 hurricanes, 617-618 for hurricanes, 627 deep convection (see thunderstorms), 481-601 theorem for cyclogenesis (Sutcliffe), 456 shaped tornadoes, 577 parameterizations in NWP models, 751 tornadoes, 583 CYVR (Vancouver International Airport), 646-647 deepening of lows (cyclones), 463 dew, 93 definition errors, 875 dew-point deformation, 320-321 depression, 93 internal Rossby radius of, 319-320, 344, 665 hygrometers, 111 use in coastally trapped jets, 664-665 temperature, 89, 92-93 D use in Rossby waves, 372-373 constant (isodrosotherm), 18 D-grid, 753 external Rossby radius of, 405-406, 665 definition, 92-93 daily cycle (diurnal), 687 frontal, 410, 433 in thunderstorm environment, 499-502 of thunderstorms, 528 shearing, 320-321 measurement, 111-112 daily solar effects, 32, 40, 687 stretching, 320-321 plotted on weather maps, 275, 438, 500 daisyworld , 813-815 total, 321 reported in METAR, 270 Dalton minimum in solar activity, 803 degrees diabatic damage angle unit, 870 effects in frontogenesis, 411 paths Celsius (°C), unit of temperature, 870 excess water variation, 187 cycloidal vs. divergent, 593 latitude & longitude, 4 heating, 131 parallel, 584 temperature symbols (°C, °F, K), 7 role in cyclone evolution, 465-466 potential (CDP) for hurricanes, 607 deka (10), 870 numerical weather prediction model, 747 scales del operator, 458 process, 61, 131 hurricane, 605-607 deluge, 607 warming rate for frontogenesis, 411 tornado, 579-580 dendrite snowflake/ice-crystal, 198-199, 843 diagnostic equations, 747 wind, by hurricanes, 634-636 optics caused by, 842-843 diagrams damming of cold air behind mountains, 661-665 dendrochronology (tree ring dating), 803 Hovmöller, 824-825, 830 damped density reliability, 782-783 inertial oscillation, 311 at sea level, 10 ROC, 783-784 response (negative feedback), 806 change with height, 10, 316 thermo, 63, 119-158 dark constant (isopycnic), 18 DIAL (differential absorption lidar), 112 band, Alexander’s, 841 current, 655-656 diameter of rain drops, radar observed, 247-248 spot ( evolution), 582 definition, 10 diamond dust (ice crystals), 276, 396, 842, 849 Darkness, by Lord Byron, 805 forecast equation for, 746 dice, 184 dart leader (lightning), 567 hailstone, 549 difference, finite, 872 data ice, 209 differential abuse, 826 interface, 657-661 absorption lidar (DIAL), 112 analysis methods of average tropospheric air, 72, 880 advection (see also castellanus clouds), 164 on weather maps , 280, 765-768 of droplet laden air, 14-15, 202 equation, 16, 137, 872 (also see statistical methods) of liquid water vs. temperature, 835, 880 heating, 329, 334-339 assimilation and analysis, 765-768 sea water, 880 heat transport by global circulation, 338-339 element, 875 mean background state, 316 meridional temperature gradient, 335-336 empirical orthogonal function (EOF), 820-823 partial, 91 radiative forcings, 329, 334-339 ethics and abuse, 826 scale height, 10 reflectivity, 256-257 extrapolating, 826 snow, 209 diffraction, 858-861 fudging, 826 specific volume, 10 fringe, 858-860 manufacturing, 826 standard (STP), 880 diffuse arcs, 854-855 massaging, 826 units, 10 diffusion, 185, 196-197 misinterpretation, 729 dependent variable, 3, 872 definition, 196-197 outliers, 502 deposition equation, 196-197, 731 principal component analysis (PCA), 820-823 latent heat of, 56, 88 of water molecules, 185, 196-197 reduction, 502, 823 nucleation, 194-195 diffusive growth of reporting, 875 depression droplets, 196-197 set, 875 tropical, 613-614 ice crystals, 198-202 slanting, 826 wet-bulb, 94-96 diffusive moisture flux, 196 smoothing, 826 depth diffusivity, 196-197 statistical (see statistical methods) Ekman layer in ocean, 378 (turbulent), 715 void, Pacific, 287-288, 765 evaporation rate, 108 molecular, 196-200, 880 databases, 772 liquid-water equivalent, 107, 208, 210 diffusometer, 46 date line, international, 5 of atmospheric boundary layer, 144, 319, 687-705, difluence, 410, 433 daughter storm, 485 716 behind cold front, 433 Davenport-Wieringa roughness-length classifica- of the troposphere, 143, 163, 357-360, 414-415 dilation, axis of, 320-321, 410 tion, 700 optical, 43, 805, 856 dimensionless ratios day parameter (Ekman) in ocean, 378 Froude number, 659, 667 duration, change of, 376 precipitable water, 98-99, 211, 501 Richardson number, 141-142, 521 sidereal, 297 precipitation rate, 108 Rossby number, 313 unit, 870 derecho, 489, 491, 494 curvature, 306 winds (anabatic; valley; sea-breeze), 649-657 derivative scales for pollutant dispersion, 736 daylight finite-difference approximation, 16, 872 dimensions, 870 duration of, 32-33, 40 total, 872 basic & derived, 870 time (DT) = daylight savings time, 5, 6 derived dimensions, 870 fractal, 171 daytime (convective) boundary layer, 692 Des Moines, Iowa, 745, 776 units, 870 dazzled by bright sunlight sky, 842 Descartes, Rene, 2, 90, 680, 841 conversions, 871 dB (decibels), 246 descending air (see subsidence) dimethyl sulfide, 188, 811 dBZ (decibels of radar reflectivity factor), 246-247 descending node of satellite orbits, 228-229 dinosaurs, 805 hail, 247-248, 552 description of global circulation, simplified, 330-334 dipoles DCAPE (see downdraft CAPE), 557-558 Arctic, 824 Deardorff velocity, 69, 703-704, 736 descriptor on weather maps, 276 Indian Ocean, 824 deaths caused by desert pressure couplets, 340 downbursts of air and aircraft crashes, 563 Gobi, 397 direct downpours of rains and flash floods, 548 oasis effect, 74 cell, 377 hurricanes and storm surge, 606, 617, 631, 637 subtropical, 351 circulations, 351, 376-377, 462 lightning, 564 suface heat flux at, 74 frontal, 412, 462 tornado outbreaks, 583-584 design of an NWP system, 761 climatic response, 806-812 winter storms, 434-435 destabilization current (DC), 564 debris cloud, tornado, 581-583 of air to make cumulus clouds, 162 instruments (in situ), 219 decade on logarithmic graph axis, 215 of well-mixed fog, 176-177 sense, 332-333, 357, 377, 456 Deccan traps, 805 to maintain a circulation, 342 vertical circulation cells, 351, 376-377 D R. STULL • PRACTICAL METEOROLOGY 891

vs. indirect heating, 73 of flux, 64, 109-110, 715 warm frontal, 401 direction of of mass, 318-321, 340 drop (see also droplet) scattered light, 857 of Q-vectors, 460-462, 469-471 deformed, 203, 255, 841, 860 wind, 2, 3 outflow straight-line thunderstorm winds, 252- diameter as affects radar returns, 247-248 frequency; wind rose, 646-647 253, 560-561 flattening, 203, 255, 841, 860 isogon, 18 plotted on a weather map, 441, 449 number in cubic meter of air, 188, 194, 201, 207, directional shear, 509-510 pressure tendency at MSL, role in, 463-467 245-246 directions of up and down, 298 radar observations of, 252-253, 560-561 optics, 837-841, 856-861 dirt, 188 term in vertical vorticity eqn., 447-448 radius, 185 dirty window, 220-223 upward motion driven by, 452-459 shapes, 203, 255, 545-546, 841, 860 disaster DMSP (defense meteorological satellite program), size distribution, 185, 545-546 plan, 638 273 terminal velocity, 203 relief, 631 dogs, sun, 842, 850-851, 854-855 typical sizes, 185 supply kit, 638 doing science, 877 volumes, 185 discomfort indices (humidity), 117 doldrums, 331 droplet, 185-218 discontinuity (tropical), 281, 399 domain of NWP, 750 curvature and solute effects, 198-192 Discours de la Méthod (book), 2 dome (overshooting thunderstorm top), 483 growth effects, 189 discretization, 750 dominant wavelength of lee Rossby waves, 444 growth by diffusion, 196-197 equations of motion, 758-759 Doppler growth rate, 196-197 discriminate between event and non-event, 783 dilemma, 251 max droplet radius via diffusion, 187 discriminator, statistical, for thunderstorm forecasts, displays, 250-254 nucleation, 188-194 507 dual radars, 249, 253 optics, 837-841, 856-861 disdrometer, 210 maximum unambiguous velocity, 250-251 radius, 185 dispersion, 723-744 phase shift, 250 equivalent, 203 color, 834-835, 862 radar (see also radar), 241, 249-254, 552 increase with time, 197 equation, 731-732 downburst & gust-front detection, 556-560 maximum via diffusion, 187, 197 Deardorff method for unstable ABLs, 735-737 locations worldwide, 272 size distributions, 185, 207 factors of pollutants, 724-725 radial wind speed (isodop), 18 lognormal, 207 atmospheric turbulence, 724-728 thunderstorm diagram, 493 Marshall-Palmer distribution, 207 plume rise, 724 shift, 241, 249-250 terminal velocity, 202 wind speed and direction, 724-727 Doswell III, Charles, 517, 567, 583-584 typical sizes, 185 far from source, 732 dot product, 239 dropsonde sounding, 134, 322, 496 fog, of, 175-177 doubling of carbon dioxide, 812 locations worldwide, 272 in neutral and stable boundary layers, 708, 732- down, direction defined, 298 drowning due to 734 downbursts and gust fronts, 482-483, 554-563 hurricane rain and storm surge, 632-637 in unstable boundary layer, 708, 735-737 bursticane, 602 thunderstorm flash floods, 547-548 isotropy, 727 causes, 555-556 dry (see also unsaturated), 57 near pollution source, 732 evaporative cooling, 556 absolutely unstable, 140 of light into colors, 834-835, 862 precipitation drag, 555 adiabatic lapse rate, 59-64, 880 Newton’s work on, 862 characteristics and definition, 554-555 to determine static stability, 139-141 of pollutants and smoke, 708, 723-744 downdraft CAPE (DCAPE), 557-559 adiabatic process Pasquill-Gifford turbulence type, 727-728 pressure perturbation, 559-550 adiabats, 63 relation of waves, 369 geographic locations, 556 labeled by potential temp, 63 baroclinic; planetary, 372 intensity estimates from radar, 561 on thermo diagram, 119-158, 497 barotropic; Rossby, 369 outflow straight-line winds, 560-563 air statistics, 728-730 radar observations of, 253, 560-561 gas constant, 880 displacement triggering new thunderstorms, 525, 561 in highs, 390 distance, 677 vertical velocities, 557-559 in thunderstorm, 497 of fluid, causing buoyancy, 135 downdraft specific heat, 880 dissipation CAPE (DCAPE), 530-531, 557-559 bulb temperature, 94, 111 length scale, 709 dangerously fast (downbursts), 554-563 lifting of air parcels, 129 of fogs, 175-177 equilibrium level (DEL), 557 lines, 416-417 of turbulence, 315, 706, 709 forward-flank (FFD), 483 airmass boundary, 416 rate, 709 rear-flank (RFD), 482 distance moved over time, 416-417 stage of thunderstorm-cell evolution, 485 speed, 554, 557-559 radar observations of, 248-249 stage of tornadoes, 583 downshear propagation of derecho, 494 triggering thunderstorms, 525 subrange, 315 downslope winds , 652-653, 667, 675-677 weather-map symbols for, 281, 399 dissipative turbulent behaviour, 706 Antarctic, 676 neutral stability, 140 distance Bora, 675-676 tongue of air in cyclone, 429 between cloud droplets, 194 Foehn, 676-677 drying in downslope winds, 676-677 between crest and trough (jet stream), 367-374, katabatic, 652-653 dual Doppler radar, 249, 253 453 mountain waves, 667 ducting of radar beam, 244-245 between sun and earth, 30, 797-802 storms, 667, 675 dummy index, 875 displacement, 677 downwelling radiation, 44-45 duplicatus, 169 distribution downwind mountain process, 443-446, 666-668 duration of rain (IDF curves), 208 Junge, 188-189 drag dust, 151, 170 lognormal atmospheric boundary layer, 699-702 airmass characteristics, 391 cloud sizes, 170 coefficient, 300, 700-701 lithometeors, 205 drop sizes, 207 range, 300, 700-701 storm (Haboob), 562 of pressure in hurricane, 618-633 force, 300-301 weather-map symbols for, 275-276 of radiation, 39 related to antitriptic wind, 312-313 swirl, 583 of smoke concentrations, 734, 737 related to BL & BLG wind, 307-311 dynamic Weibull, for wind speed, 645 sign convention, 300 frontogenesis, 411-412 disturbance on air by falling rain, 202, 555 hail mitigation methods, 554 tropical, 613 on falling heating, 672-674 upper-level, 433 cloud droplets, 202 numerical stability, 759, 773-777 diurnal (daily) cycle, 27, 356, 687 hailstones, 204 pressure, 559, 672-674 heat, 73-76, 528, 687-698 ice crystals, 842 stability, 141 of dry line, 416 rain drops, 203 Richardson number, 141 of thunderstorms, 528 on tornado rotation, 586 turbulence determination, 142 radiative fluxes, 27, 44, 687 precipitation, 555 temperature, 672-674 winds, 699-704 role in katabatic wind, 653 warming, 672-674 divergence, 318, 320-321 skin, 668 dynamical instability, 141-142 airmass formation, role of, 393-394 Stokes law, 202-203 dynamics, 289-328 aloft in wave, 668 frontal strengthening, 411-412, 469-470 low-pressure region, 432, 452-459, 463-467 parameterization in NWP, 751 hurricane, 617 tropical upper tropospheric trough, 612-613 drainage winds (see katabatic winds), 397 nonlinear, 773-776 at surface in a high-pressure region, 331, 390, drawing weather maps by hand, 280-281 numerical weather prediction, 749-750 691 drifting snow, weather-map symbols for, 275-276 topics, 1-2 evolution vs. cyclone evolution, 467 drizzle, 207-208 in pressure systems, 340-341, 467 area coverage, 546 jet-stream winds, role in cyclogenesis, 427-428, drops, 546 432, 452-459 rate and symbols on weather maps, 208, 275-276 892 INDEX E

shear, 522 of sun vs. time, 32 wind difference, 522 elf, 563, 568 E gravity, 298 Eliassen, Arnt, 759 e, base of natural logarithms, 9 inflow ellipsoid, Earth shape, 298 E-grid, 753 base, 590 elliptical orbits, 27-28 early rainout, 553 layer into thunderstorms, 590 eccentricity variations, 797-803 Earth layer for thunderstorms, 522 elves, 563, 568 albedo, 793-794 radiation emission temperature, 794 emagram (a thermo diagram), 119-152 angular rotation rate, 297 variation with temperature, 794 pre-storm soundings plotted on, 496-499 average storm relative helicity (eSRH), 590 full, 152 global energy budget, annual, 797 surface heat flux, 68, 110 simplified, 127 surface temperature, 12, 793-797 surface mixing ratio, 109 Emanuel, K. A., 625 axis, 34, 798-801 surface turbulent heat flux, 68 embryo, hail, 549-553 blackbody radiation emitted, 37, 39, 794 surface water vapor flux, 110 emerald green sun during green flash, 862 buldge of Earth at equator, 3-4 temperature, 117 emission(s) characteristics, 3-4, 879 thunderstorm depth, 522 limits for pollutants, 724 climate vertical circulation, 377 of radiation, 36-38, 41-42, 219 precession, 798-803 effervescence, 812 blackbody, 36-38 processes, natural, 793-832 efficiency of Earth temperature, 794 constants, 879 droplet coalescence, collision, collection, 204- trading, 742 daisyworld, 813-815 205 emissivity, 37, 41-42 eccentricity, 28, 34, 797-802 thunderstorms, 547 and Kirchhoff’s Law, 41, 220 variations and climate, 797-803 wind turbines, 647-648 infrared (table of typical values), 42 effective radiation emission temperature, 794, e-folding surface, 45 879 definition, 9, 879 with water vapor feedback, 810 emission of radiation, 37-39 distance, 9 emittance, 36 energy budget, annual average, 797 Rossby radius of deformation, 344 empirical, 700, 715 frameworks, 3-4 sunlight through cloud top, 131-132 orthogonal function (EOF) analysis methods, gravity, 227 height, 8-9 820-823 greenhouse effect, 795-797 of stable boundary layer, 696 wind profiles, 699-705 mass, 28 ratio, 879 encroachment method of ABL growth, 394-395, 697- moon barycenter, 27 time, 9 698 obliquity (tilt of axis), 34, 797-802, 879 airmass formation, 393-396 energy variations and climate, 797-803 EHI (energy helicity index), 530-531, 591-592 balances, Earth climate, 795-797 orbital factors, 27-34, 797-802, 879 eigenvalues and eigenvectors, 822 budget plastic, 298 Einstein, Albert (quotations), 54, 99, 235 equation, 672 precession (axial, aphelion, equinox, climate), Ekman global annual mean, 797 799-801 layer depth, 378 chemical, 54 radiation balance, 793-797 pumping, 319 conservation along streamline, 671-672 radius, 3-4, 11, 879 spiral in the ocean, 378 convective available potential (CAPE), 503-508, average volume; at poles; at equator, 879 transport, 378, 610, 632-633 530-531 rotation rate, 34, 227, 297 Ekman, V.W., 399 dimension of, 870 change of, 376 EL (equilibrium level), 483 flow, 669-672 controlling sub-tropical jet latitude, 350 El Chichon volcanic eruption, 805 flux density, 221 satellite observations of, 228-234 El Niño, 818-820 heat, 53-86 shape, 3-4, 298, 879 cyclone track, influence on, 430 helicity index (EHI), 530-531, 591-592 snowball, 811 southern oscillation (ENSO), 818-820 internal, 54, 672 sun distance, 30, 802, 879 electric kinetic, 150, 647, 669-672 aphelion, average, perihelion, 879 charge, 564, 870 dissipation in hurricanes, 625 surface origin in thunderstorms, 564-566 turbulence, 708-709 parameterizations, 751 field, 255, 565 latent, 54 temperature, 793-797 strength, 565 lightning, 564 tectonic plates, movement of, 804 electrical mechanical, 625, 670 tilt of axis (obliquity), 30, 797-802, 879 charge & units, 870 nuclear, 54 viewed from space, 220, 228, 232-233 current, 564, 870 bomb, 499, 548 volcanism, 804-805 units, 870 -per-unit-mass diagram (emagram), 122 easterlies, easterly energy, 564 potential, 150, 503-508, 669-672 African jet and wave, 611-612 potential, 564, 870 propagation via waves, 658 polar, 352 gradient, 565 released in a tropical trade wind, 330-332, 351 units, 870 hurricane, 620, 625 wave and hurricane triggering, 611-612 power, 564 thunderstorm, 499 low-altitude convergence, 612 generation by wind turbines, 647-648 sensible, 54 Eastern surges in electric lines, 569-570 thermal, 672 Hemisphere defined, 4 raindrop growth affected by lightning, 206 thunderstorm, 499, 546-548 time zone, 5 resistance, 564, 870 turbulence, 708-709 eccentricity of Earth’s orbit, 28, 797-803 units, 870 units, 870 echo voltage, 564 wave, 658 -free vault, 493, 552-553 electricity wind, 647-648 hook, 494 generation by wind turbines, 647-648 work, 503 intensity (=dBZ), 246 in a channel, 564 shaft, 672 radar, 493 lightning, 564 engine, hurricane as, 620-625 weak region, 493, 552-553 in a volume, 565 engineering ecliptic, 30 electric field, 565 boundary layers in wind tunnels, 689 ECMWF (Europ. Ctr. for Med.-range Weather Fcsts.), static, 564 creativity in, 288 271 electrification of clouds, 564-566 enhanced Fujita (EF) scale for tornadoes, 579-580 locations of weather data worldwide, 271-273 electromagnetic ENIAC computer, 749, 759 economic value of forecasts, 784-785 radiation speed, 243-245, 834 enormous hail, 548 EDT, Eastern daylight time, defined, 5 spectrum, 220-223, 834-835 ensemble, 776 eddy, eddies, 706 upwelling radiation, 220 average, 776-777 -correlation fluxes, 713 waves, 219-226, 833, 837, 856-863 calibrated probability forecasts from, 777 -diffusion theory, 714-716 electrometeors, 205 forecasts, 776-777 diffusivity (K), 715, 731 electron prediction system (EPS), 776 large, 716 charge of, 565 spread vs. skill, 777 microscale, 708 movement in a lightning channel, 565 uncertainty forecasts, 777 motions, 69, 705-706 electrosphere, 565 ENSO (El Niño Southern Oscillation), 818-820 planetary scale, heat transport by, 378 elements enthalpy, 53, 58, 671 size in ABL, 706 data, 875 entrainment turbulent, 138 of a good weather briefing, 765 at high-pressure regions, 390 viscosity, 715 elephant, 669 flux-ratio method to estimate, 698 whirls, 708 elevated thunderstorm inflow, 522 of dry air edge of smoke plume, 730 elevation angle, 4-5 into boundary layers and clouds, 57, 111, 649, EF (enhanced Fujita) scale for tornadoes, 579-580 defined, 4 694 effective of sun and radiative flux, 40 behind thunder shock front, 572 bulk E R. STULL • PRACTICAL METEOROLOGY 893

velocity or rate into ABL top, 394-395, 697-698 calibration, 875 exceedences of pollution concentration, 725 zone, 692 check for, 15 excess water mixing ratio, 186-187 entrance region of jet streaks, 454-456 correlation coefficient, 779 exercises, explained entropy definition, 875 numerical problems, 21 adiabat, 18 experimental conditions, 875 synthesis questions, 25 hurricane, 624-625 first guess, 766 tips for doing homework exercises, 20 isentrope, 18 fluctuating conditions, 875 understanding & critical evaluation, 23 on thermo diagrams, to define tephigram, 122 forecast , 777-785 web-enhanced questions, 24 thunder, 571 imperfect technique, 875 exhaust system of hurricane, 614, 618-621 total, 624-625 instrument calibration, 875 exit region of jet streaks, 454-456 environment judgement, 875 exitance, radiant, 36 Canada, 284 mean, 778, 875 exobase, 13 Hurricane Centre, 617, 638 absolute, 778 exosphere, 6, 13 Meteorological Service of Canada, 638 squared, 778 exothermal chemical reactions, 64 on a thermo diagram, 134 measurement, 875-877 experimental-condition errors, 875 thunderstorm (pre-storm), 496-499 numerical (round-off, truncation, etc.), 759-761 expert vs. novice scientists, 72 environmental observation, 766 explained variance (square of correl. coefficient), lapse rate, 59, 134 personal, 875 779 in mixed layer, 692, 697-698 precision, 875 explosive Protection Agency (EPA), air-quality standards, probabilistic forecast, 782-784 cyclogenesis , 426 7 propagation, 876-877 growth of thunderstorms, 527 sounding, 59, 134 random, 777, 875-877 pressure increase, due to pre-thunderstorm, 496-499 repeatable, 875 air stagnation, 674 temperature profile, 59 root mean square (RMS), 778 lightning, 571-574 wind (and thunderstorm motion), 516-520 small disturbances, 875 exponential EOF (empirical orthogonal function) analysis meth- standard deviation, 875-877 curve of the wind profile, 677-678 ods, 820-823 systematic, 770, 777, 875 relationships and semi-log graphs, 873-874 EPA, Environmental Protection Agency, air qual. uncertainty, 875-877 external Stds., 7 verification, 778 forcings (inputs) to feedback processes, 806 episodes, air pollution, 741 escape velocity, 6 Rossby-radius of deformation, 405-406, 665 epitaxial substances, 195 eSRH (effective storm-relative helicity, 590 trigger mechanism for thunderstorms, 496-499, epoch EST, Eastern standard time, defined, 5 525-526 Holocene, 799 estimating 22 degree angles, 847 extinction (coefficients, cross-section), 43 Pleistocene, 799 eta coordinates for NWP, 746 extrapolating data, 826 equation(s) ethical issues, 218, 826 extratropical cyclones, 330, 425-480 Bernoulli’s, 559 EU air-quality standards, 725 atmospheric boundary layer within, 690-692 coupled, 747 Euclidian geometry & dimensions, 171 baroclinic zone support, 427-429 diagnostic, 747 Euler, Leonhard, 759 birth and growth (cyclogenesis), 426-432 error propagation through, 876-877 Euler method of finite differencing, 757 bomb, 426 forecast, 293 Eulerian case study , 433-443 hypsometric, 17 definition, 53 100-50 kPa thickness chart, 439 Navier-Stokes, 759 equations of motion, 713, 746-749 overview and storm track, 433-434 nonlinear, 747 framework, 34-35, 53 storm data, 434-435 of motion, 293, 301-302, 314-317, 713, 746-749 heat budget, 64-73, 746 surface weather, 438, 466 anabatic winds, 649-652 advection, 65-67 vertical cross section, 441 analytical solution, 749 conduction and surface fluxes, 67-69 upper-level charts, 439-441, 443, 448-449, boundary-layer winds, 307-308 cooling and heating of air parcels, 60-64, 159- 451-452, 455-456, 459-463, 466 discretized, 757-758 160 central-pressure evolution, 435 for slope flows, 652 equation, 64-65, 73 clouds, 400-401, 425-428, 691-692 horizontal, 301-302, 314, 652 first law of thermodynamics, 64-65 convergence of horizontal winds, 691 katabatic winds, 652-653 latent heat, 72 death (cyclolysis), 426-432 typical magnitudes for terms, 301 net heat budget, 73 deepening, 427, 463-467 vertical velocity, 315-317, 508, 554-558, 649 radiation, 71 definition, 425-426 of state, ideal gas law, 14-15, 746 turbulence, 69-71 descending air in cold sector, 433 of time, 34 unsaturated, 64-73 development, rapid, 426 primitive, 747 momentum budget, 293, 314-315, 746 diffluence behind cold front, 433 prognostic, 747 streamlines, 668 direction of movement, 430-433 scalar, 746 water budget, 107-111, 746 evolution, 427-429 Young-Laplace, 215 horizontal advection, 107 , 426 equator, 4, 330 precipitation, 107-108 graveyard, 431 -to-pole temperature gradient, 335-336 surface moisture flux, 108-109 lifetime, 431 equatorial, 330 turbulent transport, 109-111 marine, 414-415 airmass code, 392 EUMETSAT, 228 meso (see mesocyclone), 492, 518, 586-592 heating excess, 338-339 Europe, airmasses in, 397 midlatitude (lows), 331, 425-480 high-pressure belt aloft, 350-351 European centre for medium-range weather fore- models (Norwegian; Shapiro-Keyser), 414-415 trough, 331, 350-351 casts, 271 movement, 429-430 winds, 343 (ECMWF), 271 Norwegian model, 414-415 equatorward propagation of cyclones, 446 evacuation, 638-639 sea-level pressure tendency, 463-467 equilibrium evaporation, 88 diabatic heating, 465 geostrophic adjustment, 405 of water from droplets, 189-193, 556 mass budget, 463 conditions in daisyworld: homeostasis, 813-815 net, 92 net pressure tendency, 466-467 earth’s heating, 334-339, 793-797 rate from the surface, 108 Shapiro-Keyser cyclone model, 414-415 height (or level), 483, 733 rate of solutions, 190-193 Southern Hemisphere, 426, 430-432 humidity, 87-96 zonally-averaged, vs. precipitation, 210 spin-up, 427, 446-450 level (EL), 483, 496-506 evaporative application to typical weather patterns, 450 relative humidities, 190-193 cooling of falling rain, 556 quasi-geostrophic approximation, 449 saturation, 87 rain gauge, 210 vorticity tendency, 447 supersaturation, 88, 191 events tilt of trough axis, 622 vapor pressure, 87-90 air pollution, 725, 741 transition of hurricanes into, 615 equinox, Spring (vernal) and Fall (autumnal), 30-31, binary/categorical, verification of, 780-782 translation speed, 431 800 evolution upward motion, 451-462, 691 precession, 800-801 computational, 680 continuity effects, 452-456 equipment factor in the radar equation, 245-246 of omega equation, 456-459 equitable threat score, 782 atmospheric boundary layer, 692-699 Q-vector estimates of, 460-462 equivalent potential temperature, 104-106 cyclones (extratropical lows), 427-429 vigor, 446 on weather maps, 500 fogs, 173-177 warm-air sector, 425-428 equivalent radius of drops, 203 hurricanes, typhoons, tropical cyclones, 608- winds around, 305-307, 690-692 erosion (scour) of beaches by ocean waves, 634-635 616 extreme error(s), 875-877 mixed layer, 692-698 rainfall rates, 208 accuracy, 875 thunderstorm cells, 484-485 turbulence for aircraft in thunderstorms, 529 anomaly correlation, 779 tornadoes, 583 eye of hurricane, 604-605, 618-619 background, 766 wind profile in boundary layer, 699-700 eyewall, 604-605, 618-619 bias, 770, 778, 875 exa (1018), 870 replacement cycle/double eyewall, 605 894 INDEX F

no-feedback, 807, 809 fluid positivie (amplified), 807, 809 air, 1 runaway, 807 mechanics, 1 sensitivity, 810 object immersed in, 135 F turbulence, 704-705 flux faces of ice crystals, 842 water vapor, 810 advective, 35 factor (of) feeder conduction, 73-76 attenuation, in the radar eq., 245-246 cells for hail, 549 constant flux layer, 692 beta, 368-369, 879 feeder flow in sea breeze, 655 covariance vs., 710-713 Coriolis, 297-299, 879 femto (10–15), 870 defined, 34 equipment, 245-246 Fengyun weather satellite, 228 density, 34 feedback, 806-807 Fermi, Enrico, 669 divergence, 64, 109-110, 715 reflectivity, Z, 245-246 Ferrel Cell, 332-333, 357, 377 dynamic , 35 faculae (surrounding sunspots), 803 fetch, 631, 634 eddy-correlation, 713 Fahrenheit, degrees, defined, 7 few clouds (coverage), 170, 279 effective surface turbulent heat, 68 fair weather (synoptic high pressure), 645 Feynman, Richard (quotations), 132, 167 energy, 221 cumulus (humilis), 161, 498 FFD (forward-flank downdraft), 483 form of turbulent continuity eq., 714 turbulent heat flux, 69-70 fibratus/fib, 168 gradients, 64 winds generated thermally, 645 field, 280 ground heat, 73-76 Fairy Morgan (Fata Morgana), 862-863 mill, 565 heat , 34-35, 711-712 faith, 680, 877 of height, mass, pressure, wind, 343, 359 kinematic, 35, 698, 711-713 Fall (autumnal) equinox, 30-31, 801 of temperature, 280, 343, 359 latent heat at surface, 73-76 fall filling of lows, 429, 432-433, 463-467 longwave radiative, net, 45 line (downslope direction), 652 filter mass, 34-35 velocities of cloud droplets, 159 camera moisture, 108 winds, 675 haze, 857 momentum, 712-713 falling pressure, 463 polarizing, 856 vs. Reynolds stress, 712-713 symbol on weather map, 278 Kalman, 770 radiative, 35, 221 false alarm, 780 Findeisen, 201-202 -ratio method, 698 rate, 781, 783-784 Finlayson, 817 Richardson number, 709-710, 739 ratio, 781 fine particulates (PM10) and aerosols, 188, 725 related to PG types, 710 family fine-resolution grids, 752 sensible heat at surface, 73-76 disaster plan, 638 fine-scale turbulence, 315 sign of, 74 of tornadoes, 584 finite curve, 9 surface heat, 73-76 fan/fanning, pollutant plume, 708, 710, 727 finite-difference surface moisture, 108 far approximations, 872 turbulent , 35, 698, 711-713 field pollutant dispersion, 732 spatial gradients, 754-755 FNMOC (Fleet Numerical Meteorology & Ocean. infrared and ultraviolet, 222-223 temporal gradients, 757-758 Ctr.), 608 Faraday cage, 570 equations, 754-759 Foehn winds, 676-677 farads, F, 7 numerical weather prediction (NWP), 745-792 wall (cloud), 676-677 fast-response weather instruments, 112 finite volume model - version 3 (FV3), 751 fog Fata Morgana, 862-863 fires (forest, wild, bush) caused by lightning, 564 channel on satellites, 231 fatalities (see deaths) CO2 release, 812 dissipation, 175-177 favored latitudes for hurricane formation, 609 firn snow, 209 in satellite images, 234 features of clouds, 168-169 first nuclei, 177 fecund daisyworld, 815 guess, 766 processes, 173 Federal Meteorological Handbook No. 1, USA, 268 NWP analyses, 765-767 types, 173 Federation of Atomic Scientists/American Scientists, satellite retrievals, 239 fogs, 170, 173-177 218 law of thermodynamics, 53, 58-59, 64-65 advection, 173-175 feedback, 793, 806-812 power, 873 atmospheric boundary layer, 159, 173-177 aerosol, 811 fitting an elaphant, 669 dissipation of well-mixed fogs, 173-177 amplification (positive feedback), 807-809 fixed point attractor, 790 formation, 98, 173-177 atmospheric processes, 1 fjord winds (gap winds), 661-664 frontal, 173 biological flanking line, 482-483, 492, 494-495 models, 173-177 CO2 feedback, 812 flash(es) radiation, 173-177 homeostasis, 813-815 floods, 487, 547-548 steam, 173 climate change, 810-812 green, 862 stratified, 175-177 biological CO2, 812 lightning, 567-569 upslope, 173 cloud, 811 flat surface of water, vapor pressure over, 87-90 vs. clouds, 159, 173 ice-albedo (surface), 808-812 flattened rain drops, 203, 255, 841, 860 weather-map symbols, 275-276 infrared radiation, 810 flight operations near downbursts, 563 folds in tropopause, 364, 414-415 lapse-rate, 810-811 floating, 135 isentropic potential vorticity, 364, 443 ocean CO2, 812 point operations per second (flops), 761 radionuclide injection at, 364 water-vapor, 810 floccus/flo, 168 footprint, 734 cloud, 811 floods/flooding associated with forced convection, 710 concepts/basics, 806-807 coastal, 632-635 related to PG types, 710 daisyworld, 813-815 extratropical cyclones, 425, 434-435 force(s), 295-302 damping (negative feedback), 807-808 hurricane caused storm surge, 632-635 advection, 294-295, 301 equation, 808-809 inland, 637 apparent, 299 example, idealized, 807-810 return period (IDF curves), 208 balance of, 302-314 blackbody radiative equilibrium, 807-808 thunderstorm caused flash floods, 487, 547-548 buoyancy, 135-136, 316-317, 554 ice-albedo feedback, 808-810 urban, 637 negative, 554-559 external inputs and forcings, 806 flops (floating point operations per second), 761 centrifugal, 296-297, 301 factor, 806-807 flow centripetal , 296-297, 301 forces and winds, 302 adiabatic compressible, 671-672 convection (buoyant), 135-136, 317, 503-508, 648 gain, 806-810 along a streamline, 669-672 Coriolis, 297-299, 301 different definitions, 807 around hills dimension of, 870 ice-albedo, 808-810 balanced with mass fields, 763-765 driving horizontal winds, 289-328 infrared radiation, 810 canopy, 677-679 driving vertical winds, 554-559 internal, 806 classification: subcritical, critical, supercritical, horizontal, 295-302, 301 lapse rate, 810-811 659-661 imbalance of (causing centripetal force), 305-312 linear, 806 compressible, 671-672 in Netwon’s 2nd law, 292, 294 approximation to ice-albedo process, 808 energy, 669-672 net, 292, 294 approximation to nonlinear system, 806 field in forecast models, 764 pressure-gradient, 295-296, 301 multiple processes, 807 incompressible, 669-671 summary table, 301 negative (damped), 793-794, 807 isothermal compressible, 671 thunder, 571-574 nonlinear, 806 laminar, 669 turbulent drag , 300-301 ocean CO2, 812 meridional, defined, 330 units, 7, 292, 294, 870 positive (amplified), 807 stability, 138-142 vertical, 301, 554-555 reference state, 806-809 steady state, 669 forcing (radiative) and responses (fluxes), 74 response, 806-810 through a constriction, 660 forecast, weather ice-albedo, 808-810 zonal, defined, 330 accuracy, 777 negative (damped), 807 fluctuation-condition errors, 875 blow up, 760 F, G R. STULL • PRACTICAL METEOROLOGY 895

case study, 433-443, 448-456, 459-463, 466, 745, freon, 796, 811 lifting of air layers, 140 768-770, 776 frequency line on weather maps, 280-281, 399 clouds, to aid in, 166 angular, 36 pre-frontal waves, 400, 656 confidence, 776 beat, 828 propagation using Q-vectors, 470-471 cost/loss decisions, 784-785 Brunt-Väisälä, 136-137 scale, 315 difficulties, 527 circular, 36 shear, 407 equations dimension of, 870 slope, 403-405 Eulerian, 293 of light, 36 strength, 408-412, 469-470 relative vorticity, 447 of occurrence of wind symbols, 223, 281, 399 wind velocity, 293 directions (plotted as wind rose), 646-647 thunderstorms, 400 error, 777-785 speeds, 645-646 tilting, 412 vs. time into future, 775, 780 of oscillation, 136-137 venting of boundary layer air, 691-692 hurricane, 637-639 of rain or floods (IDF curves), 208 vorticity, 407 lightning, 569 of tornadoes in USA & Canada, 579 wave (early cyclogenesis), 427-428 max surface temperature, for thunderstorms, relative, 645 winds aloft, 407 506, 523 vs. probability, 645 zone(s) models, 637, 751 shift (Doppler), 249 deformation at, 410 nowcasts, 552 units, 870 drawing on weather maps, 280-281 numerical, 745-792 friction identification, 280-281, 403 outlooks, 528-530 molecular, 301 relationship to frontal inversion, 403-407 persistence, 778-780 velocity, u*, 677, 700-713 strength, 408-412 post-processing, 770-772 typical values, 701 strengthening, 469-471 probabilistic, 777 for air, 378, 700-713 frontogenesis, 407-412 verification, 782-784 for water, 378 definition, 407-408 probability of hurricanes, 638 frictional drag dynamics, 411-412 quality, 777-785 in hurricane boundary layer, 625 kinematics, 408-410 ranges issued: outlook, watch, warning, 528-530 on oscillating air parcel, 136-137 Q-vectors, 469-471 nowcast, short, medium, long, seasonal, cli- vs. stress, 700-702 quasi-stationary, 281, 399 mate, 768 frigate sails, 635 thermodynamics, 411 refinement, 770-771 fringes, 858-861 vorticity and updrafts, 407 Kalman filter, 770 index, 859-860 weather-map symbols for, 281, 399 model output statistics (MOS), 770 front(s), 280-281, 399-424, 389 frontogenetic, 408 schedule, 762 adiabatic processes, 408-410 frontolysis, 409 scientific basis for, 746-751 aloft, 281, 413-414 weather-map symbols for, 281, 399 short-range (nowcasts), 552 ana-, 404 quasi-stationary, 281, 399 skill, 752, 777-784 analyzing, 280-281, 402 frost as affects growing crops, 653 vs. time into future, 775, 780 attributes of, 399 frostbite, 77 thunderstorm intensity, 501, 507, 516, 521-522, bent-back, 414-415 frost-point 524, 527-531 between two boundary layers, 691 hygrometer, 111 tornadoes, 530-531, 588-592 cold, 399-400, 525 temperature, 92 uncertainty, 776 aloft, 399 Froude number, 659-661 verification, 777-784 genesis, 399 1. For surface or interfactial waves, 659 watches & warnings, 528-530, 638 triggering hurricanes, 612 2. For internal waves, 659 forecasters (human), 772 depth, 403 3. For flow over hills, 667-668 forest drawing, rules, 280-281 fudging data, 826 canopy, 677-678 drylines, 399, 525 fuel death (waldsterben), 742 dynamics, 411-412 for hurricanes, 620 fire formation, 408-413 for thunderstorms, 99, 499-502, 547-548 clouds, 166 geostrophic adjustment, 404-406, 412 fossil: climate change issues, 812 CO2 release, 812 glyphs (lines) on weather maps, 399 Fujita (F) scale for tornadoes, 579-580 lightning causing, 564 gust, 482, 525 fulgurite, 570 nuclei from, 195 horizontal structure, 400-402 Fuller, R. Buckminster, 804 forging data, 826 kata-, 404 fumulus, 166 formation and growth of kinematics, 408-410 functions , 872 airmasses, 389-399 labeled by temperature, 281 fundamentals of atmospheric boundary layer, 689-692 lake-breeze, 525 science, 869-878 fogs, 173-177 layer stability affected by, 140 weather radar, 240-245 highs (anticyclones), 391 locating, 280-281 , 483, 581-583 thunderstorms, 496-499 lows associated with, 389 weather-map symbols for, 276 forward occluded, 281, 399, 413-414 fusion, latent heat of, 56 -flank downdraft (FFD), 483, 492-495 over-riding air, 407 FV3 (finite volume model-version 3), 751 -flank precipitation area, 483 polar, 352 problem, 235 rotation around lows, 389 scattering, 219, 857 sea-breeze, 525, 654-657 trajectory, 724 Shapiro-Keyser cyclone model, 414-415 fossil fuels and climate, 812 squall line, 400 G Fourier-transform spectrometers, 47 stationary, 281, 399, 404 gaia hypothesis, 813-815 fractals , 414-415 gain, feedback, 806-811 definition, dimensions and cloud shapes, 171 strength, 408-412 different definitions of, 807 errors in measuring, 875 structure, 400-417 gale, 635-636 vs. Euclidean geometry, 171 horizontal, 400-402 Galileo, 315 fraction of vertical, 403-407 gamma rays, 222 pollutants in air, 724 surface, 399-412 gap winds/flows (for long and short gaps), 661-664 sky covered by clouds, 277-279 thermodynamics, 411 gas fractus/fra, cumulus, 165-166, 168, 483 thunderstorm triggers, 525-526 anthropogenic greenhouse, 796, 811-812 scud, weather-map symbols for, 277 upper-level (upper-tropospheric), 414-415 constant frame of reference, 2-4 vertical structure, 403-404 for dry air, 14, 572, 880 on Earth, 3-4 warm, 399-401, 525 for water vapor, 14, 88, 880 framework: source-receptor, 724 aloft, 399 ratio, epsilon, 91, 554, 880 free genesis, 399 ideal gas law, 14-15, 572 atmosphere, 687, 690-695 weather-map symbols for, 280-281, 399 natural greenhouse, 805, 811-812 convection, 704, 710 winds above, 407 gases level of (LFC), 497-506 frontal atmospheric (constant and variable), 7 related to PG types, 710, 727-730 analysis, 280-281, 402 water vapor, 87-118 smoke dispersion during, 735-737 baroclinic zones, 427, 469-471 greenhouse, 811-812 sink level (LFS), 557 boundary on weather maps, 280-281 on other planets in the solar system, 22 freezing clouds gauges, rain and snow, 210-211 crops, 653 cumuliform at cold fronts, 162 Gaussian level altitude and hail formation, 551 stratiform at warm fronts, 162-164 curve, 184, 729-730, 875 nucleation, 194-195 fog, 173 plume dispersion, 729-731 precipitation change criterion for SPECI, 270 forecasts, 427-429, 768 distribution of concentrations, 729, 737 rain, 195 inversion, 403-404, 691 parameters, 729-730 weather-map symbols, 276 jets, 357-359, 407, 472 profile, 729 896 INDEX G, H

GCMs (global climate models -or-, 815-816 carbon cycle, 812 Eötvös effect, 317 general circulation models), 768 climate models (GCMs), 379, 768, 815-816 force, 301 Geiger, Rudolf, 817 circulation, 329-388 measurement, 317 GEM (global environ. multiscale) model, 751 anticyclones (highs), formation locations, Newton’s discover of, 293 GEM-PAK, 772 391 reduced, 135-136, 316, 658, 670 gene expression programming, 680 explaining, for various latitudes, 350-356 waves, 658-661, 666-668, 710 genera (clouds), 168 heat transport by, 338-339 thunderstorm triggering, 526 general circulation (see global circulation), 329-388 steering hurricanes, 607-608, 615 great dying, 805 models, 379, 768 three-band, 329, 376-378 Greeks, 205, 444 three-band, 329, 376-378 environmental multiscale (GEM) model green generation of electricity by wind, 647-648 geopotential height patterns, 355 color defined (also see optics chapter), 37, 834 genesis of heat flash, 862 airmasses, 392-397 budget, 166 sun, 862 anticyclones (highs), 390-391 transport, 338-339 greenhouse effect, 795-797 genetic insolation, 41, 336-337, 793 greenhouse gas(es), 724, 796, 805, 811-812 bottleneck, 805 lightning mapper (GLM) on satellite, 235 from volcanoes, 805 programming, 680 nomenclature, 330 Greenland, 396 geographic information systems, 274 population vs. hurricane disasters, 631 ice cores, 803 geography of positioning system (GPS), 112, 291 Greenwich Mean Time (GMT), 5 lightning, 564 pressure patterns, 354-355 Greenwich Meridian, 4, 28 North America, 431 radiative forcings, 41, 793-794 Gregorian calendar, 31 Pacific Northwest (USA & Canada), 661 telecommunication system (GTS), 268 Grenfell, Sir Wilfred, 737 geomagnetic effects on Earth’s rotation, 376 temperatures, 335 GRIB = gridded binary, 268 geometric warming, 150, 796 GRID code, 269 albedo, 831, 879 influence on hurricanes, 631 grid(s) height, 11 glory, 859-860 Arakawa A to E, 753 measurement by GPS, 291 Morning, 656 box, 750 optics, 833 glow, zero-order, 841 cell, 750 scattering, 857 glyphs (symbols) plotted on weather maps, 275-279, ghost, 756 sunrise and sunset, 33-34 614-615 computation rules for NWP, 756 geometry GMT (Greenwich Mean Time) defined, see UTC, 5 nested, one-way and two way, 752-753 of atmospheric optics, 833-868 Gobi desert, 397 points, 749-756 of light rays, 833-868 GOES satellite, 226-228 resolution, 750, 752, 761, 816 geopotential, 11, 304 16 satellite, 222-235 staggered, 753 height, 11 ABI (advanced baseline imager), 222-235 variable, 752-753 errors, 766 channels for imager and sounder, 222-223 volume, 750 global map example, 355 orbits, 227-228 grooming machines for snow trails, 209 N. American map examples, 433-442 Goethe, 249 ground measurement errors, 766 GOMS satellite, 228 clutter in radar returns, 243-245, 254 geostationary satellites, 227-228 Gondwana; Gondwanaland, 804 subsurface heat and moisture parameterizations, GOES, 228-229 governing equations, 746-750 751 international, 228 GPS (Global Positioning System), 112, 291 growing days for crops, 653 METEOSAT, 228-229 GPU (graphics processing unit, on computers), 763 growth weather observation locations from, 272 gradient rates for ice crystals, 200 geostrophic definition, 15, 295, 872 rate of daisies (daisyworld), 814 adjustment, 343-344, 406, 412 of flux, 64 rate of droplets, 196-197 part 1, 344 of pressure, 295-296 GTS = global telecommunications system, 268 part 2, 349 of temperature, vertical, 872 Gulf Stream current, 431, 616 part 3, 404-407 of wind or momentum, 295 gust approach to geostrophy, 303-304 Richardson number, 710 1 to 10 minute average, for hurricanes, 607 balance, 302-304 supergradient wind, 643 3-second, for tornado speeds, 579 departure, 314 transport theory, 714-716 gust fronts (related to downbursts), 482, 494, 554-563 paradox, 459, 462 wind, 304-307 relative vorticity, 319 imbalanced, 619 arc & shelf clouds along, 532 vorticity, 319 in anticyclones, 306-307, 391 depth of, 562 Laplacian form, 450 in cyclones, 306-307, 432 dust storm (haboob), 562 wind, 302-304, 343-349 in hurricanes, 609, 617-619 speed of, 562 at cold front, 405-407 subgeostrophic, 304 radar observations of, 253, 556, 560 at equator, 343 supergeostrophic, 304 triggering new thunderstorms, 525 at mountains, 662-664 supergradient, 643 , 582 changes with altitude, 345-349 GrADS, 772 changes with latitude, 303 GRAF code, 269 for atmospheric boundary layer, 699 graffito (the singular of graffiti) (see Science Graffiti) gap, 663-664 related to thermal wind, 345-349 grain size of snow, 199 H temperature advection, 458 granddaughter storm, 485 habits, ice crystal, 198-200 vs. actual wind, 303 graphics processing unit (GPU), 762 haboob (sand storm), 562 wind speed, 303 graphing, 873-874 Hadley cell, 329, 332-333, 350-351, 357, 377-378 related to isobar packing, 303 abscissa, 3 influence on worldwide rain distribution, 209 related to tilt in isobaric surfaces, 359 axes, 3, 873-874 heat transport in tropics, 339, 378 geostrophy, approach to, 303-304 linear, 9, 873 mixing caused by, 335-336 GFS (global forecast system) model, 751 log-log, 215, 874 hail, 199, 205, 548-554 ghost grid cells, 756 slope, 215 change criterion for SPECI, 270 giant meteorological variables, 3, 9 damage from, 532, 549-554 CCN, 206 ordinate (vertical) axis, 3 embryo, 549-554 hail, 247, 548, 553 power, 874 forecasting, 530-531, 550-552 giants, on the shoulders of, 294 pressure as height variable, 9-10, formation, 549-550 Gibbs free energy, 217 relationships, 873-874 giant, 548, 553 Gifford-Pasquill turbulence types, 727-728 semi-log, 9, 873-874 location climatology, 552-553 giga (109), 870 graupel(n), 199, 205, 546-554 mitigation, 553-554 gigabit, 870 lightning, role in creating, 564-566 nucleus, 549 Gilbert’s skill score, 782 weather-map symbols for, 276 radar observations of, 247-248, 552-553 GIS (geographic information systems), 274 graveyard for extratropical cyclones, 430-432 shaft, 552 giving a weather briefing, 765 gravitation law (Newton’s), 11 significant hail parameter (SHIP), 530-531, 551- glacial/interglacial (ice age) periods, 795, 799 gravitational 552 glaciated clouds, 482, 485 acceleration on Earth, 15, 879 streak, 552 glacier ice, 209 variation with latitude & altitude, 879 suppression, 553-554 glaciogenic, 553 constant, Newtonian, 6, 15, 879 swath on the ground, 163, 548, 552 Gladwell, Malcolm, 924 force, 15, 301 weather map symbols for, 276 glass windows, transparency of, 45 gravity, 14-15 hailstones, 185, 548-554 GLM (global lightning mapper, on satellite), 235 current, 355-656 fall speeds, 204, 549 global Earth’s, 227, 298 layers, 550 albedo, 793-794 effective, 298 size classification (TORRO scale), 548 H R. STULL • PRACTICAL METEOROLOGY 897 hair hygrometer, 111 heavy rain, 207-208, 545-548, 637 monsoon-related, 333-334 halo, 845-855 weather map symbols for, 276 named (Bermuda, Pacific, etc.), 354-356 22 degree, 842, 845-846, 854-855 hectare unit of area, 870 polar, 331, 352, 391 46 degree, 842, 846, 854-855 hecto (102), 870 ridges, relationship to, 390 arctic airmass ice-cloud, 396 Pascals, defined, 7, 8 Southern Hemisphere, named highs, 354 associated with pyramid crystals, 847 Heidke skill score, 781 subtropical, 391 circumscribed, 851, 853-855 height thermal (cold), 341-342 clouds that enable, 163 cloud-base, 130, 278 tilt with altitude, 390 luminous meteors, 205 constant, map at, 436 vertical structure, 391 numerical computation, 756 contours on an isobaric map, 18, 121, 151, 290- weather associated with, 390 others, 853-855 291 winds around, 305-307, 390-391 rare halos: 9, 18, 20, 23, 24, 35°, 847, 854-855 errors, 766, 778 resolution, 752 viewing angles, 846-847 field, 343 risk, high gain science, 863 vs. corona, 860 geopotential, defined, 11 thunderstorm risk, 530 halocarbons (e.g., freon; CFC-12 & others), 796, 811- isohypse, 18 Higher Math boxes, 11 812 of smoke plume centerline, 723, 729, 733-734, 736 Adiabatic Lapse Rate, 60 Halsey Jr., Admiral William F. , 807 of temperature inversion, 144, 496-499 Advection Fog, 173 hand analysis of weather maps, 279-281 on weather maps, 436-437 Apparent Forces, 299 Handbook on Chemistry and Physics, 879 on isobaric charts, 439-441 Bernoulli [Equation] Derivation, 670 Hansen and Kuiper’s score, 781 tendency (isallohypse), 18 Beta Plane, The, 369 Hastings arcs, 854-855 tiling method for CAPE, 504-505 Betz’ Law, 648 Hawaii time zone, 5 vs. pressure, 8, 9 Brunt-Väisälä Frequency, 137 Hawaiian high, 354-356 relative maximum/minimum of height, 290 Calculus, 872 hazards relative minimum/minimum of temperature, Clausius-Clapeyron Equation, 89 coastal, 634-635 138 Critical Radius, 193 hurricane, 631-637 scale heights for pressure and density, 8-10 Cumulative Heating, 693 lightning, 569-571 tendency forecast equation, 463-467 Diffusion Equation, 731 thunderstorm, 545-602 variation of weather variables, 11-13 Error Propagation, 876 haze, 170, 191-193 vs. pressure, 290-291 Explanation of purpose of these boxes, 11 filters for cameras, 857 heirarchy of operational forecast models, 768 Feedback Example, 809 lithometeors, 205 heliac arc, 854-855 Geopotential Height, 11 scattering of light in, 856-858 helicity, 587-592 Geostrophic Adjustment, 406 weather map symbols for, 276 energy helicity index (EHI), 530-531, 591-592 Hypsometric Equation, 18 HDT, Hawaii daylight time, 5 hodograph, determination using, 588-589 Incremental Changes, 38 head, sea-breeze, 655 mesocyclone, 587-592 Info Projection, 239 headwinds, aircraft, 563 storm relative (SRH), 530-531, 588-592 Laplacian, The, 450 heat, 53-86 effective, 590 No-feedback Response, 807 adiabatic process, 60-64 tornado indices, 588-592 Non-equilibrium Winds [at hurricane top], 619 balance, 64, 94 updraft (UH), 530 Omega Equation, The, 458 budget, 64 helium, He, 7 Physical Interpretation of Equations, 16 closure problem, 713-714 Helmholtz, Herman von, 759 Pressure Reversal, 623 equation, 64, 73, 713, 746-747 Helprin, Mark, quotations, 13, 171 Q-vector Omega Equation, 462 Eulerian, 64-76, 713, 746-747 Hemispheres Taylor Series, 755 Lagrangian - saturated, 101-106 Eastern & Western defined, 4 Temperature Gradient, 336 Lagrangian - unsaturated, 57-64 Northern & Southern defined, 4 Thermal Wind Effect, 346 net, 73, 713 hemispheric weather maps, 441 Turbulence Terms, 714 surface, 73-76 hertz (Hz), unit of frequency, 870 Vorticity of a Wave, 368 capacity changes due to precipitation, 121 heterogeneous nucleation Warm Core Winds, 623 conservation equation, 58, 64-76, 746 freezing, 194-196 highs (see high pressure centers), 354, 390-391 engine, 624-625 liquid water, 188-194 highways, as threat to safety, 517 enthalpy, 58, 671 heuristic approach , 371 hills, flow over, 397-398, 472, 487, 526, 649-676 flux, 34-35 heuristic (toy) models, 280, 330, 793 Himalaya mountains, 397 airmass modification by, 397 hexagonal ice crystals, 198, 842-843 hindcast, 762 at top of mixed layer, 698 columns, 198-199, 842-843 history of bottom of ABL, 693-698 dendrites, 198-199, 843 Beaufort wind scale, 635 curvature, 375-377 hollow columns and needles, 198-199 numerical weather prediction, 759 effective surface turbulent, 68 needles, 198-199 hit, 780 kinematic, 34-35, 698 optics, 842-855 rate, 781, 783-784 sinusoidal variation, 693 plates, 198-199, 842-843 hockey-stick (Keeling) curve, 812 top of ABL, 698 pyramids, 198-199, 842 hodograph, 510-522 turbulent, 711-715 sheaths, 198-199 basics, 510-513 vs. height, 698 Hg (see mercury), 7, 19 blank, which you can copy, 512 vs. time, 693 high using for thunderstorm prediction, 514-522 index, 77-78, 117 altitude sea-breeze, 656-657 internal sources, 64 clouds (stratospheric & mesospheric), 166 storm-relative island, urban, 678-679 winds (upper-tropospheric), 331-332 helicity, 588-589 latent, 53-56, 72, 101-106, 546, 880 clouds, 162-163, 168 winds, 585 condensation, vaporization, 56, 880 height variation with latitude, 163 hollow ice crystals (needles, columns), 198-199, 866 deposition, sublimation, 56, 880 weather-map symbols for, 168, 277 Holocene epoch, 799 fusion, melting, 56, 880 Earth orbit satellites, 227-228 Holt, MO, 547 lightning, 567 humidity needed for formation of homeostasis, 813-815 net budget, 72 hurricanes, 609-610 homeothermic, 76 released in thunderstorms, 546-548 thunderstorms, 496, 499-502 homework exercises (at end of each chapter) sensible, 53-56, 671 latitudes, defined, 330 answers (see Solved Examples) specific, 53, 55 global circulation, 352 tips and explanations, 20-26 stress, 77-78 monsoon, 333-334, 354, 391, 615 homogeneous stroke, 78 order truncation finite-difference scheme, 754- freezing nucleation, 194 surface budget of, 73-76 755 nucleation of liquid water droplets, 188-191 thermodynamics, 1, 53-86 plateaus, influence on drylines, 416-417 homogenization, 109, 689 transfer coefficient, bulk, 68 precipitation supercell, 495 Hong Kong Observatory (HKO), 607 transferred, 58, 672 wind statistics for, 585 hook echo, 494 transport pressure center (H, see also anticyclones), 389- horizontal achieved, 338-339, 378 391 advection by jet stream (Rossby waves), 374-375, 378 airmass creation within, 389-399 of heat, 65-67 global, 338-339, 378 aloft, in hurricane core, 613 of momentum, 294-295 needed, 338-339 boundary layer within, 390, 690-692 of total water, 107 to compensate radiative differences, 338-339 convergence at top of, 391 of vorticity, 447-449 vs. latitude, 329, 335-336, 339, 378 descending (subsiding) air in, 356, 390 circulation, 365-366 urban heat island, 678-679 divergence at bottom of, 390 method for finding, 365-366 heating formation locations, 391 convergence, 252-253, 318-321, 340-341 cumulative, 693-694 isobars around, 390 coordinates, alternative, 747 differential, 329, 334-339 meso-, 391, 488, 554, 559 divergence, 318-321, 340-341 dynamic, 672-674 mid-latitude, 331, 389-391 aloft, 449, 452-459 898 INDEX H

equations of motion, 301-302, 314 condensation energy, 620-621 -ocean interactions, 610 forces, 294-302 core, 604, 615, 618-625 outflow, 618-619 advection, 294 Coriolis force, 609 over land, movement, 616 centrifugal & centripetal, 296-297 cyclone, 426 Pacific, 631 Coriolis, 297-299 cyclogenesis (birth), 608-610 power, 620, 625 in slope flows, 650-651 cyclolysis (death), 615-616 precipitation, 615 pressure-gradient, 295-296, 619, 650-651 damage prediction, 637-638 turbulent drag, 300 potential, 607 pressure, 618-623, 626, 633 IR flux gradient, 71 scales, 605-607 reversal with altitude, 621-623 local, 4 dangerous portions, 627 probability of threat, 638 motions, scales of, 315 disaster relief, 631 radar observations of, 254 plates (ice crystal), 198-199, 842-855 Dolly, 606 radial winds, 627-628 roll vortices, 167 drag against the sea surface, 625 rain bands, 604, 613-615 scales vs. dynamics, 617-619 rainfall rate, 620 forecast skill, 768 inflow and outflow, 618-619 research aircraft, 637 time scales, 315 initial spin-up, 617 right quadrant (most dangerous), 627 structure of fronts, 400-402 subsequent development, 617-618 Rita, 605, 637 turbulent transport , 71-72 easterly jet and waves (from Africa), 611-612 safety, 637-638 velocities, 314 Ekman transport, 610 Saffir-Simpson hurricane wind scale, 605-606 vorticity (streamwise), 518, 586-587 El Niño/La Niña effects, 631 satellite observations of, 603-605, 608, 614, 616, advection of, 447-451 energy, 620, 625 620, 637 tilting of, 586-587 entropy, 624-625 sea-surface temperature (SST), 608, 616 winds, 302-314 evacuation, 638-639 season, 630 , 331 evolution, 608-616 social issues, 631 hot exhaust system of, 614, 618-621 spiral bands, 604 convective towers, 644 extratropical stages in life cycle, 613-615 film anemometer, 321 cold fronts, triggering by, 613 steered by global circulation & monsoons, 607- wire anemometer, 321 systems, collision with, 616 608, 615 hour transition, 615 Azores high, 607-608, 615 angle, 41, 801-802 eye, 604, 615, 621 Bermuda high, 607-608, 615 glass shaped tornadoes, 577 downdrafts in, 605, 620, 628-629 Hawaiian high, 615 unit, 870 photo inside, 637 trade winds, 607-608, 615 Hovmöller diagram, 824-825, 830 eyewall, 604, 615 storm surge, 632-634 Howard, Luke, 168 double, 605 atmospheric pressure head, 632 howling sounds (aeolian tones), 560 replacement cycle, 605 Ekman transport, 632-633 HP (high-precipitation supercell), 495 second, 605 Kelvin wave, 633-634 hPa (hectoPascal) definition, 7-8 Floyd, 605, 608 structure, 604-605 HST, Hawaii standard time, 5 force winds (Beaufort scale), 635-636 surface wind-waves, 634-636 hub height, 647 forecasting, 637-639 symbols on weather maps, 614-615 human formation requirements, 608-606 temperature (air), 621-622, 624, 629 population & zoning for hurricanes, 631 Frances, 606 thermodynamics, 620-625 humidex, 77-78, 117 frequency, 630 Carnot cycle, 624-625 humidity, 87-118 fronts from midlatitude, interaction with, 612- diagram, 624 absolute, 14, 91 613 warm core, 621-623 airmass, 391-392 fuel creation, 620 thunderstorms, 609 comfort indices, 77-78 geographic distribution, 605-609, 615 hazards, 637 constant (isohume), 18 global warming effects, 631 tornadoes and tornado outbreaks in, 584, 627, dew-point temperature, 92-93, 499-500 glyph (symbol) on weather maps, 426, 614-615 637 equivalent potential temperature, 500 hazards, 631-637 total entropy, 624-625 errors, 766 Hazel, 617 tracks (translation speeds & directions), 607-608, gradient, 196-197 heat engine, 624-625 615, 627 high (needed for thunderstorms), 499-502 hot convective towers, 644 triggers, 610-613 hurricane cyclogensis conditions, 609-610 Hugo, 639-670 tropical indices of discomfort, 117 human population and zoning, 631 cyclone, 426, 615 instruments, 97, 111-112 humidity needed, 609-610 depression, 613-614 isohume, 18 hunters, 637 disturbance, 613 lifting condensation level (LCL), 93-94, 501 idealized, 605 Prediction Center, 638 mean-layer, 501 identification (ID) number, 613-614 storm, 614 liquid water potential temperature, 500 incipient, 612-615 TUTT (tropical upper tropospheric trough), 613 mixing ratio, 91, 95, 500 -induced ocean currents, 610 , 426 precipitable water, 98, 501 Inez, 621 intensity scales, 607 relationships between moisture variables, 87-97 inflow, 618-619 vertical relative , 92, 95 initial spin-up, 617 cross section, 605, 618, 620-622, 624, 629 satellite observations of, 226, 234, 273 instability (nonlocal conditional) & CAPE, 609 velocity, 629 saturation, 87-96 insurance, 631 vorticity in environment, 610 saturation level, 93-94 intake system of, 614, 618-620 warm core, 614-615, 618-625 sensors, 97, 111-112 intensity, 605-607 warning, 631, 638 specific, 91 Isabel, 604, 616, 627 watch, 638 thunderstorm convective conditions, 496, 499- Isis, 614 weak wind shear in environment needed, 610 502 ITCZ, 610-611 winds variables, 91-96 Ivan, 606, 614 gust averaging time, 605 vs. dew point temperature, 95 Javier, 614 vs. geostrophic adjustment, 384 weather maps of, 500-501 Juan, 617 shear in hurricane environment, 610 wet-bulb temperature, 94-95, 104, 500 Katrina, 603-604, 616, 620 tangential, 622-623 humilis/hum (cumulus), 161, 168 kinetic energy dissipation, 625 total (tangential + translational), 627 humisery, 117 latent heat release, 620-624 zoning and landuse, 631 humiture, 117 latitude of formation, 608-615 Huxley, Aldous (quotations), 38, 236 hunter, hurricane, 637 life-cycle, 613-615 Huygens, Christiaan, 837 hurricane(s), typhoons & tropical cyclones, 330, 603- moat, 605 Huygens’ Principle, 837, 859 644 model, 626-629 hybrid along coastlines, 631-635 composite picture, 629 coordinates in NWP model, 746 Andrew, 606, 643 pressure distribution, 626 supercell thunderstorm, 492 bands, spiral rain, 604 radial velocity, 624-628 HYDRA code, 269 boundary layer flow, 618-619 tangential velocity, 626-627 hydrate, methane, 810 Canadian Hurricane Centre, 617, 638 temperature, 629 hydraulic(s) Carnot cycle, 624-625 vertical velocity, 628-629 jump, 656, 660-662 category, 605-606 monsoon trough, 612 open-channel, 657-661 Charley, 606 movement (translation), 607-608, 615 hydrogen, H2, 7 circulation of air through, 620-625 names for, 426, 614-615 hydrogen peroxide, 190-192 classification, 605-607 retired, 615 hydrometeor(s), 185 cloud shield, 604 National Hurricane Center (NHC), 638 definitions, 205 cold water, movement over, 616 natural 40-year cycle, 631 graupel, 205 composite picture, 629 non-equilibrium winds, 619 hail, 205 H, I R. STULL • PRACTICAL METEOROLOGY 899

number, 187 , 356 subrange, 708 radius, 187 ideas, 99 subrange turbulence scale, 315 size, 187 ideal gas law, 14-15 transformation, 715 terminal velocities, 202-204 gas constant, 14, 880 wind, 312 hydrometeorologists, 257 idealized inferior mirages, 83, 861-862 hydrometer(s), 111 feedback example, 807-810 infinite hydrophilic, 188 fog models, 173-177 loop, 759 hydrophobic, 218 hurricane model, 626-629 number of equations, 714 hydrostatic winds, 302 inflection points, 730 assumption/definition, 15-16 identification of inflow balance, 15-16, 316 clouds, 161-169 layer (info box), 590 equation, 15-16, 316 hurricanes, using numbers and names, 613-615 winds into thunderstorms, 483 use of, for isobaric surfaces, 296 lines (isopleths) on thermo diagrams, 126-127 elevated inflow base, 522 equilibrium, 15-16 different types of thermo diagrams, 126-127 Info boxes thermal circulations, 341-342, 655 identity matrix 30 - 30 Rule (for lightning safety), 570 HYFOR code, 269 IDF (intensity, duration, frequency) of rain, 208 A Holistic Approach to Stability, 139 hygrometers, 75, 97, 111-112, 219 IEEE standards board, 870 Ageostrophic Right-hand Rule, 455 hygroscopic igneous meteors, 205 Albedo, 794 cloud seeding, 553 image(s) Alternative Horizontal Coordinates, 747 pollutants, 191 interpretation of satellite photos, 231-233 Alternative Vertical Coordinates, 746 hypothermia, 77 radar reflectivity, 243, 246, 248, 254 Amdahl’s Law, 763 hypoxia, 874 imager, 230 Anabatic Slope Flow, 651 hypsometric channels on satellites, 222-223, 230 Approach to Geostrophy, 303-304 constant, 17, 880 imbalanced Astronomical Values for Time, 34 equation, 17-18 forces (causing a centripetal force), 305 Barotropic vs. Baroclinic, 749 sea-level-pressure reduction, 267 initial conditions, 304 Beaufort Wind Scale History, 635 use in explaining anabatic flow, 650-651 mass and flow fields, 763 Bergen School of Meteorology, 399 H2, hydrogen gas, 7 systems, tendency to reach new balance, 329 Binary Multiples, 870 H2O, (see water), 7 immersion Boiling, 90 buoyancy of objects, 135 Cap vs. Capping Inversion, 497 freezing, 194-195 CAPE vs. DCAPE, 558 impact parameter, 839-841 Climate Sensitivity, 812 imperfect-technique errors, 875 Coriolis Force in 3-D, 297 I inaudible thunder, 575-576 Cp vs. Cv, 55 IAC code, 269 incandescence, lightning, 564 Cubic Ice, 198 FLEET, 269 inches of mercury (in. Hg), 7 Cyclone Damage Potential, 607 ICAO = international civial aviation organization, incident Derecho, 494 149 angle, 833 Deriving the Radar Equation, 245 weather station ID or code, 270 light, 833-863 Downbursts and Flight Operations, 563 ice radiation, 41-47, 334-339, 793-803, 833-863 Droplet Growth, 191 ages, 795, 798-799 INCLI code, 269 E-folding Distance, 9 aggregation into snowflakes, 200, 202 inclination of satellite orbits, 228 Early History of NWP, 759 albedo climate feedback, 808-810 incoming solar radiation (insolation), 40-41, 334-337 Effective Inflow Layer, 590 cores, 803 Effervescence and CO2, 812 crystal, 185, incompressible Electricity in a Channel, 564 clouds (cirrus clouds), 163 continuity equation, 318-319 Electricity in a Volume, 565 columns, 842, 866 flow, 669-671 Engineering Boundary Layers, 689 electrification of clouds, role in, 564-566 increased water vapor, 810 Enthalpy vs. Heat, 58 faces, 842 increasing, weather-map symbol for, 276 Eötvös Effect, 317 fall speeds, 206 incremental changes, Higher Math box, 38 Escape Velocity, 6 fogs in arctic airmasses, 393-397 incus, 169, 482 Estimating 22° Angles, 847 geometry, 198-199, 842 independent Force of Thunder, 571 habits, 198-199, 842-843 observations, 236-239 Gain — Different Definitions, 807 halos, 842-855 variable, 3, 872 Geostrophic Paradox, 459 hollow columns, 198-199, 866 index Giving a Weather Briefing, 765 lattice, 194-195, 198 air quality, 743 GOES 16 Global Lightning Mapper, 235 lightning creating, role in, 564-566 discomfort, 117 Greenhouse Gases, 811 mass, 200 dummy, 875 Hail Suppression, 553 nucleation, 194-196 heat, 77-78, 117 Hurricane Condensation Energy, 620 optics (also see Optics chapter), 163, 842-855 humidex, 77-78 Hurricane-induced [Ocean] Currents, 610 plates, 842 livestock weather safety, 117 Hurricane Juan Hits Canada, 617 pyramids & pyramid optics, 842, 847 of thermal stress, 77-78, 117 In Newton’s Own Words, 292 rotation angles, 843, 845-846 of refraction Internal Energy, 54 shapes, 198-199, 842-843 light, 834-835, 880 Isosurfaces & Their Utility, 436-437 weather-map symbols for, 276 radar, 243-244 Jet Stream Aspect Ratio, 357 cubic (Ic), 198, 855 sound, 575-576 Kalman Filter, 770 density, 209, 880 summer-simmer, 117 Landfalling Pacific Cyclones, 472 embryo, 194, 549-550, 553 temperature-humidity, 77-78, 117 LeChatelier’s Principle, 132 fallout from arctic airmass, 396 thunderstorm-forecast, 530-531, 551-552 Lightning Burns the Air, 567 formation on aircraft wings, 130 wind-chill, 76-77 Lightning in Canada, 568 growth by diffusion, 198-202 India Linear Regression, 770 growth rates, 200-202 monsoon, 356 Lipschitz Continuity, 761 ice crystal habits, 198 Regional Specialized Meteorological Center, 607 Mandatory and Significant Levels, 135 Wegener-Bergeron-Findeisen (WBF), 201- Indian Ocean Map Projections, 748 202 dipole (IOD), 824 Maximum Advection on Weather Maps, 458 hail, 199 Southern Indian Ocean High, 354 Median, Quartiles, Percentiles, 502 hexagonal (Ih), 198, 834-835 indices for thunderstorm forecasting, 530-531 Meteors and Meteorology, 205 index of refraction, 834-835 indigo color defined (also see optics chapter), 37 Molecular vs. Turbulent Stress, 701 loading, 14, 555 indirect Moore’s Law and Forecast Skill, 752 melting into rain, 206 sense, 455-456 Multi-field Charts, 443 mixing ratio, 97, 186 sunlight, 33-34, 46 Newton and Colors, 862 needles, 199, 276 vertical circulation cells, 377 North American Geography, 431 nucleation, 194-196, 202 induced electric currents, 570 NWP, The Quiet Revolution, 772 nuclei, 185, 194-195 inductive reasoning, 107-109 On Naming Local Winds, 654 particles, 185, 546 industrial centers, clouds forming over, 162 Pacific Data Void, 765 pellets (sleet), 199 inefficient coalescence, 205 PCA and EOF, 821-823 weather-map symbols for, 276 inertia, 292 Polar Front, 408 phases, 198 inertial Pollution Concentration Units, 724 refractive index, 834-835 forcing, 367-371 Power of Hurricanes, 625 saturation vapor pressure over, 88 motion, 312 Rainbows and the Renaissance, 841 snowflakes, 198-200 in downbursts, 559 Resolution and Grid Spacing, 761 specific heat, 880 oscillation, 304, 311-312, 700 Rossby Number, The, 306 ICEAN code, 269 damped, 311 Satellite Retrieval Difficulties, 239 900 INDEX I

Scheiner’s Halo, 855 of rain, 207-208 chart, 437, 441 Snow Grain Classification, 199 of hurricanes, 605-607 compressible flow, 671-672 Solid-body Relative Vorticity, 363 of thunderstorms, 528-531 potential vorticity (IPV), 364-365, 441-443 Solution by Iteration, 310 of tornadoes, 579-580 conservation, 364 Some Other Satellite Systems, 230 of turbulence, 503-508 lee cyclogenesis due to, 365 Southern Hemisphere Lows, 426 of typhoons, 607 tropopause folds visible by, 364, 414-415 Special Crystal Orientations, 855 weather-map symbols for, 276 units (PVU), 364, 441 Specific Heat Cp for Air, 56 intercept, 770 upper-level fronts, 414-415 Speed of Sound, 674 intercloud lightning, 563 processes in hurricanes, 625 Spreadsheet Thermodynamics, 63, 103 interdecadal Pacific oscillation (IDPO), 824 surfaces, 437 Stratospheric & Mesospheric Clouds, 166 interface, density, 657-661 in fronts, 403, 414-415 Sun-Earth Distance, 802 light refraction across, 833 on weather maps, 437 Sutcliffe Development Theorem, 456 interfacial waves, 658-661 Islam, 754 Time Differencing Methods, 757 interference, 858-861 island, urban heat, 678-679 Time of Max Airmass Thickness, 395 constructive and destructive, 859 isobar, 17 Tornado Watch, 529 fringes, 858-861 for barotropic vs. baroclinic atmospheres, 749 Torques on the Earth, 376 interferometers, interferometry, 46-47 frontal, 400-401 Trade Inversion, 351 interglacial/glacial (ice age) periods, 795, 799 on thermo diagram, 63, 100, 119-158 Warm Airmass Genesis, 394 Intergovernmental Panel on Climate Change (IPCC), packing vs. wind speed, 303, 307 Warm vs. Cold Core Cyclones, 622 811 rules for drawing on weather maps, 280-281 What is an Oscillation, 818 intermittent tornado, 581 What is Coriolis Force?, 298-299 turbulence in entrainment zone, 692 isobaric Why Does Ro = (1-A)·So/4, 795 weather-map symbol for, 276 charts, 290-291 Why So Many Moisture Variables?, 96-97 internal for case-study cyclone, 433-466 Why So Many Thermo Diagrams?, 121 boundary layer, thermal (TIBL), 654-657 definition, 17, 290, 436 Why Use Isobaric Maps?, 291 dynamics (Bunker’s) method for storm motion, maps/charts, 290-291, 436 info projection, 239 518-520 reason for using, 291, 436-437, 442 infralateral arc, 854-855 energy, 54, 672 20 kPa, 440-443, 452, 455-456 infrared (IR) radiation (see also longwave), 27, 37-39, feedback processes, 806 50 kPa, 433, 442, 448, 451 222-223, 793-794 heat sources, 64, 72 70 kPa, 439, 442 cooling at cloud top, 484, 488-489 Rossby radius of deformation, 319-320, 344, 665 85 kPa, 439, 442, 449, 459-462 emissions from Earth system, 220, 334, 337, 794 international 100 kPa, 438, 463 emissivity (table of typical values), 42 civil aviation organization (ICAO), 149 surfaces, 290-291, 345-349 feedback, for climate, 810 cloud atlas, 168 mandatory, 772 fog formation, role in, 173-177 date line, 5 on weather maps, 290-291, 436-442 hygrometer, 111 long scale number prefixes, 870 vs. constant height maps, 290-291 in troposphere, 71 space station (obs. of hurricane & thunder- isobath, 17 rain drop growth affected by, 206 storms), 604 isobathytherm, 17 satellite images (photos), 230-233 system of units (SI), 7, 870 isoceraunic, 17 satellite sensors, 46-47, 226, 230-232 interpretation of isochrone, 17 scattering in atmosphere, 857 hodographs, 510-522 isodop, 17, 250 thermometer, 78 METARs and SPECIs, 270-279 isodrosotherm, 17 inhibition, convective (CIN), 523-524, 530-531 satellite images, 231-233 map of pre-thunderstorm environment, 500 initial weather maps, 436-472 isoecho, 17 conditions, 731, 758, 762, 816 interquartile range (IQR), 502 isogon, 17 sensitivity, 773 intertropical isogram, 17 spin-up of hurricane, 617 convergence zone (ITCZ), 233, 330-332, 350-351 isohel, 17 value problem, 293, 762 discontinuity, 281, 399 isohume, 17, 100-101 initialization intortus, 169 on thermo diagram, 100-101, 119-158 objective optimum interpolation, 766 intracloud lightning, 563 pre-storm environment, 497-499 normal mode, 766 intrinsic on weather maps variational analysis, 767 phase speed, 369, 658 rules for drawing, 280-281 inland unpredictability, 774 pre-storm environment, 499-501 flooding, 637 inundation, 632-637 isohyet, 17 sea breeze, 654 invariance, rotational, 320 isohypse, 17 input, net solar, 795 inverse problem, 237-239 isoline, 17 external forcings to feedback processes, 806 inverse square law of radiation, 39-40 isoneph, 17 inquisition, 470 inversion isopleth, 17 INSAT, 228 capping, 143-144, 496-499, 687-690 hand analysis and drawing on maps, 280-281 insects, 151 vs. thunderstorm cap, 497 of pollution concentration, 734, 737 in situ (direct) sensors, 219 frontal, 403-404, 691 isopycnic, 17 insolation (incoming solar radiation), 334-337 lapse rate, 140 for baroclinic vs. barotropic atmospheres, 749 average annual, 336-337 passat, 351 process behind thunder shock front, 572 average daily, 40-41, 336, 799-802 surfaces, 403, 687, 691, 695 isoshear, 17 latitude variation of, 337 temperature, 139, 687-691 isostere, 17 related to PG types, 727-728 trade, 351 iso-surfaces, utility of, 436-437 variations vs. climate variability, 799-802 iodide (cadmium, lead, silver), 195 isotach, 17, 358-359 instability Ionian age, 799 weather map of, 440, 443 baroclinic, 353, 371-374 ionized air, lightning, 565-566 isotherm, 17 barotropic, 353, 367-370 ionosphere, 565 frontal, 400-401 CAPE & thunderstorm updrafts, 503-508 ions, 564 on cross sections of atmosphere, 359 cloud-base detrainment instability, 484 IPCC (Intergovernmental Panel on Climate Change), on thermo diagram, 63, 100, 119-158 dynamic 39-45, 793-832 on weather maps, 280, 400-402, 427, 439-440, 608, and chaos, 773-776 IR (also infrared, terrestrial, or longwave radiation), 768-769 and the Richardson number, 141-142 37-39 rules of drawing, 280-281 line, 281, 399 thermometer, 78 isothermal nonlocal conditional (thunderstorm), 496, 503- iridescence, 165, 667, 685, 859-860 compressible flow, 671 508 irradiance (see also radiation), 36 lapse rate, 140 nonlocal conditional (hurricane), 609 irregular ice crystal shapes, 199 isotropic, 8, 221, 315 numerical, 759-761 irreversible processes, 121, 131, 765 defined, 8, 707-708, 727 instantaneous irrotational winds, 385 force, 8 smoke plume, 728 in tornado, 577, 602 motions and scales, 315, 707 wind part, 705-706 isallobar, 17 radiation, 221 instrument calibration error, 875 isallohypse, 17 turbulence, 707-708, 727 instrumented tower, 75 isallotherm, 17 isotropy, 707-708, 727 instruments (see weather instruments) isanabat, 17 ITCZ (intertropical convergence zone), 233, 330-332, insurance, 772 isanomal, 17 350-351 hail/crop, 553 isentrope, 17, 63, 103-105, 122-123, 143-144, 156, 365, hurricane trigger, 610-612 hurricane/disaster, 631 373, 403, 407-410, 414, 437, 624-625 thunderstorms, 331-332 intake system of hurricanes, 608-620 on case-study weather maps, 438 iterative techniques, 103, 238, 308, 310, 394-395, 573- integral/integration, approximation for, 872 on vertical cross section, 441 576 integrated circuits (computer chips), 752 isentropic intensity analysis, 144, 364, 437, 441, 443 J, K, L R. STULL • PRACTICAL METEOROLOGY 901

temperature units, defined, 7, 870 breeze, 656 wave, 633-634 surface observation from satellite, 234 J Kepler, Johannes, 27 landfalling Pacific cyclones, 472 Japan Meteorological Agency (JMA), 607 Kepler’s second law, 29 landscape vs. roughness length, 700 jet Kern arc, 854-855 tornadoes, 582 barrier, 664-665 key altitudes for thunderstorms, 496-499 land-use observation from satellite, 220 blue, 563, 568 Keyser, (Shapiro-Keyser cyclone model), 414-415 La Niña, 818-820 coastally trapped low-level barrier, 664-665 K-H waves, 142, 165, 654-655 cyclone track influence on, 430 contrails, 160 clouds (fluctus), 165, 169 Laplacian, 450, 458 climate change effects, 812 kilo (103), 870 form for geostrophic vorticity, 450 easterly, 611-612 kilobit, 870 lapse rate, 59-64, 139-140 low-level kilograms, 870 adiabatic, 139-140 coastal barrier, 664-665 force environmental, 59, 134, 140-141 nocturnal, 699-700 mass , 870 feedback in climate, 810-811 nocturnal, 699-700 kiloPascals, defined, 7-8 inversion, 140 prefrontal, 407, 433, 472 kinematic isothermal, 140 rear inflow (RIJ), 489 definition, 320-321 moist vs dry, 104-106 sting, 414-415 effective surface water-vapor flux, 110 names, 140 jet-streak, 454 flux of total water, 109-110 process, 59-64 driving updrafts and cyclogenesis, 454-456, 467 flux of water vapor, 108-110 saturated (moist), 101-106 entrance and exit regions, 455-456 frontogenesis, 408-410 standard atmosphere, 11-12, 70 four quadrants, 455-456 heat flux profiles in ABL, 698 subadiabatic, 139-140 of cyclone case study, 455-456 mass flux, 34-35 superadiabatic, 139-140 thunderstorm triggering , 526 momentum flux, 704, 715 thunderstorm environment, 496-499, 503-508 jet-stream(s), 357-361 stress, 701 unsaturated (dry), 60-64 African easterly, 611-612 surface heat flux, 73-76 vs. static stability, 139 angular momentum, 360-361 kinematics, 320-321 large aspect ratio, 357 circulation, 365-366 eddy simulation models, 786 axis, 362 convergence and divergence, 320-321 scale (global) circulation, 329-388 baroclinicity, 359-360 deformation, 320-321 laser radar (lidar), 112, 322 core, 357-359, 414-415 vorticity, 320-321 latent heat circulation around the globe, 357-358 kinetic energy condensation, 56, 465-467 curvature, 453 in Richardson number, 150 cyclogenesis, 465-471 driving updrafts and cyclogenesis, 453 of flow, 669-672 deposition, 56, 88, 880 cyclogenesis, role in, 427-429, 432 of global circulation, 356 energy, 54 easterly, 611-612 of molecules, 6 Eulerian heat budget, 72 equation, 359-361 of wind, 150 evaporation, 54 exit region, 454-456 turbulence, 708-709 factor, 56 frontal zones, at, 407 King Arthur legend, 863 flux at surface, 73-76 maximum, 357-362, 454-456 Kirchhoff’s Law, 41, 220 fusion, 56, 880 meanders (Rossby waves), 329, 357, 367-376 klystron vacuum tubes in radar, 240 hurricanes, fuel for, 620 polar, 233, 331-332, 352-353, 357-360 Knollenberg probe, 210 internal energy source, 64, 72 secondary circulations, 455-456 knot unit of speed, 278, 291, 870 melting, 54, 56 speed, 357-361 knowledge, organizing, 72 on thermo diagrams, 130-131 vs. season, 357-358 Köhler precipitation, measure of net heating, 465-466 streaks of max winds, 454-456 curves, 191 rate, 72, 465-466 subtropical, 233, 331-332, 350-351, 357-361 equation, 190 release in angular momentum effects, 360-361 Köppen climate classification, 816-817 hurricanes, 613, 620 Joint Polar Satellite Systems, 229 Köppen, Wladimir, 817 thunderstorms, 72, 465-466, 499-502, 546-548 Joint Typhoon Warning Center (US), 607 kPa (kiloPascals) defined, 7-8 self-development of cyclones, 468-471 joule, unit of energy, 870 Krakatau, 805 sign convention, 56 JPSS, 229 krypton hygrometer, 111 sublimation, 56 Juan Kuiper’s and Hansen’s skill score, 781 thunderstorms, fuel for, 499-502 de Fuca Strait, 661-663 Kuroshio ocean current, 431 vaporization, 56, 88, 880 Hurricane, 617 variation with temperature, 90, 880 judgement errors, 875 water, 54 Julian day, 29 lateral direction, defined, 727 jump latitude(s) hydraulic, 660-661 L belts, 329-330, 350-355 potential temperature, 110, 690-698 L band radar, 242 radiative forcings, 338-339 Junge distribution of cloud condensation nuclei, 189 Labrador current, 616 change with distance north, 336 lacunosus, 169 degrees of, 4, 330, 879 Lagrangian elevation angle of sun as function of, 32, 801-802 definition, 53 excluded, for hurricane formation, 609 heat budget-saturated, 101-106 high-, 330 liquid-water, wet-bulb, & equivalent poten- horse, 331 K tial temperatures, 104-106 hurricane, favored & excluded, 609 K (degrees), 7 saturated adiabatic lapse rate, 101 lines, 4 K band radar (including Ka and Ku bands), 242 thermo diagrams, 102-103 low-, 330 K index (KI), 531 heat budget-unsaturated, 57-64 mid-, 330 K-Pg event (mass extinctions), 805 adiabatic lapse rate, 60 of strongest jet-stream, 359-361 K-T event (mass extinctions), 805 first law of thermodynamics, 58-59, 64-65 Laurasia, 804 K theory, 714-716 potential temperature, 61-62 Laws Kalman filter & gain, 770 thermodynamic diagrams, 63 Amdahl’s, 763 kaolinite, 195 momentum budget, 292 Beer’s, 43, 856 Kármán, von, 677, 701 Bernoulli’s equation, 670 first law of thermodynamics, 53,58-59, 64-65 katabatic wind net source of water, 99 inverse square law of radiaion, 39-40 equilibrium speed, 653 pollutant dispersion, 731 Kirchhoff’s, 41 high pressure associated with, 391 time scale, 732 gravitation (Netwon’s), 11 in Antarctic airmass formation, 396, 676 trajectories, 669 Moore’s, 752 in Antarctic cyclone formation, 432 water budget, 99-106 motion (Newton’s), 292 in fog formation, 177 thermo diagrams, 100-101 myth of, 38 in forest trunk space, 678 water conservation, 99 Newton’s, 11, 292 in stable (nocturnal) boundary layer, 696 lake sine law of radiation, 40 vs. Bora winds, 675-676 breeze, 654 Snell’s, 834-837 katafront, 404 fronts, 525, 655-657 Stefan-Boltzmann, 37-38 Keeling curve (for CO2), 812 high pressure, 391, 655 Planck’s, 36 Keith, David, 815 steam fog, 173 Wien’s, 37 Kelvin Toba, 805 large hail, 548 circulation theorem, 366 Lamb, Sir Horace, 705 layer, 147 equation, 189-191 Lambert map projection, 748 atmospheric boundary, 687-722 Helmholtz (K-H) waves, 142, 165, 169, 654-655, laminar air flow, 138, 140, 669-671, 688 clouds, 162-164, 168 710 land method for static stability, 140-141 902 INDEX L

triggering of thunderstorms, 526 photon particles, 833 instability, 281, 399 radix, 703-705 point, 834-835 path, 668-669 stability classes, 140-141 polarization, 856-857 shear, 281, 399 layers of the atmosphere, 12-13, 563, 565, 692, 700-705 rainfall rate, 207-208 squall, 281, 399 weather-map symbols for, 276 streak, 668-669 LCL (see lifting condensation level) rays, 833-837 stream, 611-612, 668-669 LDN (lightning detection network), 568 reflection, 833-844 thunderstorms (squall line), 399, 490 lead (Pb), the chemical, 725 refraction, 833-855 linear iodide, 195-196 scattering, 856-857 depolarization ratio, 256-257 lead time in forecasting, 762 spectrum, 37, 222, 834-835, 862 feedback processes, 806 leaders speed of, 36, 240, 243, 834-837, 879 approximation to nonlinear process, 806- dart, 567 transmission of, 73, 805, 856 809 stepped, 566 ultraviolet, 222, 857 graph, 873 leap waves, 833 regression, 770-771 day, 31 lightning, 563-571 relationship, 873 -frog (time-differencing) scheme, 757 30-30 safety rule, 570 Lipschitz condition/continuity/smoothness, 761 year, 31 air discharge (cloud-to-air, CA), 563 liquid-crystal thermometers, 78 least squares, 770 anvil, lightning from, 564 liquid drop optics, 837-841 LeChatelier’s Principle, 132, 141, 329, 344, 383, 429 ball, 567 Alexander’s dark band, 841 lee cyclogenesis, 430-431, 443-446 bead, 567 primary rainbow, 839-840 conservation of potential vorticity, 364-365, 445 behavior and appearance, 566-568 reflection from water, 838 isentropic, 364-365 blue jet, 563, 568 secondary rainbow, 840-841 equatorward propagation along the lee side, 446 bolt (see return stroke), 566-567 liquid droplet nucleation, 188-194 stationary planetary waves, 443 from the blue, 567 liquid-in-glass thermometers, 78 lee waves, 666-668 breakdown potential, 566 liquid-water left burning the air, 567 content (LWC), 97 moving , 518-520 Canadian, 566 measurement, 210 quadrants of jet streak, 454-456 channel, 563-567 density vs. temperature, 835, 880 Leibniz, Gottfried Wilhelm, 759 climatology, 564 equivalent, 107, 208 length, 870 cloud-to-cloud (CC), 563 loading, 15, 555 buoyancy scale, 733 cloud-to-ground (CG), 563 mixing ratio, 97-98, 186 mixing (Prandtl), 715 C P T P, 5 69 on thermo diagram, 130 momentum-scale, 733 creation by micropysical processes, 564-566 potential temperature, 104-106 Obukhov , 703 currents, peak, 568-569 on thermo diagram, 103-106 path (radiative), 43 deaths caused by, 564, 571 on weather maps, 500 roughness, 677, 700-703 detection networks (LDN), 568-569 specific heat, 880 scales, 315 satellite low-light cameras, 569 liter (or litre) unit of volume, 870 buoyancy, 733 satellite optical transient detectors, 569 lithometeors, 205 dissipation, 709 duration, 569 litre (or liter) unit of volume, 870 momentum, 733 electrometeors, 205 livestock weather safety index, 117 units, 870 elf / elves, 563, 568 loading, liquid water or ice, 15, 555 lenticular/lenticularis/len clouds, 165, 168, 666-668, fatalities from lightning strikes, 571 local 684-685 fires (forest, wild) caused by, 564 closure, 714-716 optical phenomena caused by, 859-860 flashes, 567 elevation angle of sun, 32 LEO (low Earth orbiting) satellites, 227 flickering, 567 horizontal, 4, 5 levels forecasting, 569 shear across one layer, 514 mandatory, 134, 772 global lightning mapper (GLM), 235 winds, 645-686 significant, 134, 147 hazards, 569-571, 607 naming, 654 radar echo intensity, 247 heat, 567 location parameter, Weibull distribution, 646 level of hurricane, 637 median as, 502 downdraft equilibrium (DEL), 557 igneous meteors, 205 locations of equilibrium (EL), 483, 497-506 incandescence, 564 hail, 552-553 free convection (LFC), 497-506 intercloud, 563 strongest hurricanes, typhoons, trop. Cyclones, free sink (LFS), 557 intracloud (IC), 563 631 lifting condensation (LCL), 93-94, 496-499 jet, 563, 568 weather observations worldwide, 271-273 lidar (laser radar, including DIAL), 112, 219 median peak current, 564 logarithmic anemometer, 322 MUCAPE, 569 relationships and semi-log graphs, 873-874 image of thermals, 649 negative (polarity), 563-564 wind profile, 677 life odor, 567 logarithms, base of natural, 879 controls on climate, 813 plasma, 567 log-linear wind profile, 702-703 cycle of polarity, 563-564 log-log graph, 215, 874 hurricane, 613-615 positve (polarity), 563-564 slope, meaning of, 215 thunderstorm, 484-485 power, peak, 569 lognormal distribution tornado, 583 pressure wave in thunder, 564, 571-574 clouds, 170 lifted index (LI), 531 red sprite, 563, 568 lightning surge probabilities, 569-570 lifting ribbon, 568 rain-drop size, 207 condensation level (LCL), 93-96, 105-107, 130, 138, safety & warning signs, 567, 569-571 log wind profile, 677, 702-703 162, 164, 483, 496-501, 530-531 sferics, 568 London, Jack, 849 cumuliform cloud base, 162 sheet, 567 long height change with precipitation, 130-131, size, 563 gap winds, 662-664 398, 676-677 spider, 567 range forecast models, 768 mean-layer, 501, 530-531 sprite, 563, 568 scale number prefixes (international), 870 of chinooks and foehns, 676-677 staccato, 568 waves of lenticular clouds, 666-668 storm (see Thunderstorms), 481-602, 564 Rossby; planetary waves, 369 of upslope fog, 173 strike sequence, 566-568 radiation, 37-39 on thermo diagram, 129-130, 497-499 temperature, 563 Longfellow, Henry Wadsworth, 847 pre-thunderstorm, 497-501 thunder, 571-576 longitude, 4, 802 pressure at, 93 types, 563 longwave radiation (see infrared), 37-39, 220, 793-794 stratiform cloud base (not related to), 164 weather-map symbol for, 276 temperature at, 96 likelihood of tornadoes, 591 loom, optically, 862 tornado funnel cloud, 581 likely velocity looping of smoke plumes, 727-728, 735-737 fog, 177 downburst in thunderstorm, 557-559 loops trigger for thunderstorms, 496, 522-526, 530-531 updraft in thunderstorm, 508 radar, 241 light, 222 limit of satellite, 227 bending, 833 convection, 498 Lord Byron, 805 colors, 37, 834-835, 862 predictability, 773-776 Lorenz strange attractor, 773-775 diffraction, 858-861 line(s) Lorenz, Ed, 773, 775 electromagnetic waves, 833 absorption, 221 loss, 780 ice-crystal optics, 842-855 clouds, 167 vs. cost, 785 liquid drop optics, 837-841 convergence, 281, 399 lottery, 711 mirages, 861-863 end vortices, 490 Lovelock, James, 813 monochromatic, 833 dry, 399 low optics in the atmosphere, 833-868 flanking, 482-483 clouds (see also fog), 162, 168 L, M R. STULL • PRACTICAL METEOROLOGY 903

height variation with latitude, 163 weather 516-518 scud, 483 airmass locations, 392 error, 778, 875 weather-map symbols for, 168, 277 analysis methods, 274-281, 402 layer Earth orbit (LEO) satellites, 227 CAPE, 506-508 CAPE, 506-507 latitudes, defined, 330 surface, 267 CIN, 524 global circulation, 350-351 marine air, 656 lifting condensation level (ML-LCL), 501, level jet maritime 530-531 coastal barrier, 664-665 airmass code, 392 persistence error, 778 nocturnal, 699-700 cloud condensation nuclei, 194 running average, 599 light level cameras for lightning detection, 569 fogs, 173-174 sea level (MSL) pressure, 267, 275 order truncation finite difference schemes, 754- tropical airmass, 392 forecast equation, 464-467 755 Marshall-Palmer distribution, 207 maps, 354 precipitation supercell (LP), 495 mass, 870 reduction from station pressure, 267 wind statistics for, 585 air, in a column, or between pressure levels, 10, shear vector, 514-515 pressure 464, 466 squared error (MSE), 778 boundary-layer pumping, 319-320, 432 airmass, 389-399 skill score, 778 meso-lows, 489 budget, 317-318, 746-747 statistical definition (=average), 502, 705, 726 mountain lee, 165 of air column (for MSL pressure), 463 wind, 705, 726 systems (see extratropical cyclones), 330, 425 center of, for radar observations of, 252-253 pressure-centers (extratropical cyclones; lows; pollutants, 729 shear vector, 514-515 L), 425-480 wind vector, 516-517 vector, 516-518 fronts rotating around, 389, 425-426 conservation, 317-318, 660, 746-747 measurement of glyph (symbol) on weather maps, 426 boundary-layer pumping, 318-319 fractal dimension, 172 hurricane eye, 613-615 continuity equation, 317-318 humidity, 111-112 midlatitude, 331, 425-480 incompressible continuity equation, 318 radiation, 45-47 monsoon-related, 333-334 thunderstorm, 545-546 rainfall, 210-211 named (Aleutian, Islandic, etc.), 354-356 density, 10-13 soundings, 134-135 rising air in, 356, 451-462 Earth, 28, 879 temperatures, 78-79 thermal, 341-342 extinction events, 805 winds, 249-254, 321-322 tracks, 429-431 field, 343 mechanical winds around, 305-307, 446-450 adjustment to wind field, 343-344 clocks & time, 34 resolution NWP, 752 balanced with flow fields, 763-765 energy, 625, 670 lower in forecast models, 764 turbulent production, 704 quartile, 502 flux (dynamic & kinematic), 34-35, 317-318 Medawar, Sir Peter, 343 suncave Parry arc, 854-855 in Newton’s second law, 292 median, statistical definition, 502 sunvex Parry arc, 854-855 inflow vs. outflow, 317-319 medical symptoms for people struck by lightning, tangent arc, 851-852, 854-855 moon, 28 571 Wegener arc, 854-855 of air in column, 10 medieval maximum in solar output, 803 Lowitz of air parcel mixture, 160 mediocris/med, cumulus, 161-162, 168, 483 arcs, 855 of solute in droplet, 190-193 Mediterranean airmasses, 397 oriented crystal, 855 of water vapor, 91 medium-range weather forecast models, 768 lows (see extratropical cyclone chapter), 425-480 planets in the solar system, 22 mega (106), 870 midlatitude cyclones, 330-331, 425-480 units, 870 megabit, 870 models, 414-415 massaging data, 826 megaton bomb, energy of, 499, 548, 880 Southern Hemisphere, 426, 430-432 mathematical melting subpolar, 331 closure, 714 ice crystals, as seen by radar, 248 LP (low-precipitation supercell), 495 constants, 879 latent heat of, 56 luminary, 858 framework, 2 Mercator map projection, 748 luminous mathematics, 315, 711, 762 mercury intensity units, 870 clarity, 393 barometer, 7, 19 meteors, 205 matrix, 822 inches of, 7 lumpy cloud shapes, 161-164 covariance, 821-822 millimeters of, 7 lunar tides, 376 eigenvalues and eigenvectors of, 822 meridians, 4, 330 Lyman-alpha hygrometer, 111 trace, 822 defined, 4, 330 mature stage of prime, 4, 28 waterspout spray vortex, 582 meridional thunderstorm cell evolution, 485 displacement, 372 tornadoes, 583 flow, defined, 330 M Maunder minimum in sunspots, 39, 803 gradient (MG) of zonal momentum, 376 Mach number, 571-576, 579, 674 maximum kinematic heat flux, 374 one, 579, 674 acceptable levels of air pollutants, 725 overturning ocean circulation, 810 macroscale cloud electrification, 564-566 advection on weather maps, 458 propagation of baroclinic waves, 372-374 Madden-Julian oscillation (MJO), 818, 824 likely temperature gradient, 335-336, 352 Maddox, Bruno, 54 downdraft speed in thunderstorms, 557-559 transport by Rossby waves, of, 374-376 MAFOR code, 269 updraft speed in thunderstorms, 508 heat, 374-375 magnetic precipitation for WBF process, 201-202 momentum, 375-376 direction finders, 568 solar output, 803 wave flux, 375 field, 255 surface temperature for thunderstorms, 506, 523 Merilees, Phil, 775 variation, 647 tangential winds around eye wall, 605, 622, 626- mesocyclone (see thunderstorm), 481, 483, 492-495, magnetron vacuum tube in radar, 240 627 586-592 magnitude theoretical pressure ratio of hurricane, 625-626 counter-rotating, 490-491, 587 component of scientific notation, 870 unambiguous range, for radar, 240-241 radar observations of, 253 of total shear, 515-516 unambiguous velocity, for Doppler radar, 250- wind shear, importance for, 510 main updraft tower, 482-483 251 as affects storm-center motion, 518-520 major Hadley cell, 332-333 updraft speed in thunderstorms, 508 tornadoes, relationship to, 582, 586-592 mammatus/mamma clouds, 169, 484 vorticity advection, 458 meso-high, 488, 554, 559-563 mandatory levels for RAOBs & NWP output, 134- wave-height, 634-636 meso-low (also see mesocyclone), 489 135, 772 winds through short mountain-gaps, 662 mesopause, 12-13 Manhattan project, 218 mb, millibar, definition, 7-8 mesoscale, 315 man-made clouds, 166 MCC (mesoscale convective complex), 491 cellular convection (MCC), 167 manual (hand) analysis of weather maps, 279-281 McMahon, 817 convective Manual on Codes No. 306, WMO, 268 MCS (mesoscale convective system), 488-492 complex (MCC), 140, 491 manufacturing data, 826 role of wind shear, 510 system (MCS), 488-492, 613 map, 274-281 MCV (mesoscale convective vortex), 492 system, lightning from, 564 factors, 747 MDT, Mountain daylight time, defined, 5 vortex (MCV), 492, 613 polar stereographic, 747 mean, 502, 705, 726, 875 forces in gap winds, 662-664 NWP output, 772 absolute error (MAE), 778 gap geostrophic wind, 663 projections, 747-748 and turbulent parts of wind, 705-706, 726 high pressure (see meso-high), 488, 554, 559-563 conformal, 748 anomaly, 29 mesosphere, 12-13 Lambert, 748 background state, 316 polar clouds in, 166 Mercator, 748 bias, 778, 875 MET (Middle European time), 5 polar stereographic, 747-748 condition for air, 7 metabolism, 76 stereographic, 748 environmental wind (normal storm motion), metaldehyde, 195-196 904 INDEX M metamorphosis of snow crystals, 209 twilight, 33-34 weather-map symbol for, 276 METAR = aviation routine weather report , 170, 268- milli (10–3), 870 thunderstorm risk, 530 271, 275-279 millibars, defined, 7 modern maximum in solar activity, 803 abbreviations for precipitation, 208 minima in solar activity, 803 modification of airmass (see airmass), 397 Météo-France, 607 minimum via flow over mountains, 398-399 meteogram, 117, 745, 772 viewing angle, 846 via surface fluxes, 397-398 meteoroids, 205 visibility (in METAR), 270 Moilanen arc, 854-855 Meteorologica (book by Aristotle), 26 minor Hadley cell, 332-333 moist, 57 meteorological minute unit, 870 adiabatic lapse rate (saturated), 101-103 aviation report (METAR), 270-279 mirages, 861-863 for determining static stability, 139 conventions, 2 Fata Morgana, 862-863 adiabats, 101-106, 497 Meteorological Service of Canada (MSC), 243, 638 green flash, 862 on thermo diagrams, 102-106, 119-158 meteorology, 205 inferior, 83, 861-863 thunderstorms, 497-499 applied, 2 superior, 862 convection (thunderstorms), 496-499 Bergen School of, 399 mirrors, ice crystals acting like, 843-844 convective adjustment, 70 definition, 1, 205, 877 misinterpretation of data, 729 process, 130 disciplines or components of, 1, 353 miss, 780 moisture, 87-118 forecasting, 745-792 missed approach to airports, 563 budget at surface, 107-110 synoptic, 353 mist, 170 cyclogenesis, 426 theoretical, 872 weather-map symbol for, 276 flux, 108, 110 meteorite dust, seeding clouds, 166 mitigated loss, 780 diffusive, 197 meteoroids, 205 mixed-layer (see atmospheric boundary layer), 68, forecast equations for, 746 meteors, 11, 168-169, 205 692 instruments, 111-112 hydrometeors, 205 airmass, 393-396 transfer coefficient, bulk, 109 other meteorological meteors, 205 CAPE, 506-507 variables, 87-99 meteosat, 228-229 convective, 649, 692 moisturizing process to form clouds, 159-160 meter, 870 Deardorff velocity for, 703-704 mole, 870 methane, CH4, 7 depth, 144, 649 molecular weights (g/mole), 7 greenhouse gas, 811 determination of, 143-144 ratio of pollutants, 724 hydrates in ocean & permafrost, 810 entrainment into, 649, 697-698 molecular sulfonic acid, 188 growth, 695 compression, 7-10 method of associated with airmasses, 393-395 conduction flux, 67-69, 73 moments, 730 associated with dry lines, 416 conductivity, 67-68, 880 problem solving, 869 rate, 698 diffusivity (see also diffusivity), 196-200, 880 meticulous, 19 lifting condensation level (ML-LCL), 501 energy, 118 metric ocean, 610 friction, 301 (SI) units, 7, 870 scaling variables, 735-736 rotation lines in spectra, 221 ton (or tonne), 870 temperature profile, 692 scale, 315 Mexico time zone (MEX), 5 thunderstorm environment, 496-497 scattering of radiation, 220-222 Michelson interferometer, 46 top, 143-144, 497-499 speed & temperature, 6-7 micro (10–6), 870 transport coefficient, 68 stress, 701 microbursts, 554 unstable, 692 vibration lines in spectra, 221 microphysics (of clouds and precipitation), 185-218, winds in radix layer, 703-705 viscosity, 709 546 mixing weight, 7 parameterizations in NWP models, 751 length theory, Prandtl, 715 of air, 7 microscale, 315, 708 of air parcels to create clouds & contrails, 160- of atmospheric gases, 7, 724 processes creating cloud electrification, 564-566 161 of solute in CCN, 190 microwave ratio, 91 moments, method of, 730 bands, 223 average total water, 97-99 momentum, 292 energy from radars, 240 definition, 91 advection, 294 ovens, 243 excess water, 186-187 angular, 360, 375 radiation, 220 gradient, 196 subtropical jet, 360-361 rain sensors, 211 ice, 97, 186 budget, 292-293 refractometer, 111 liquid-water, 97-98, 186 Eulerian, 293, 746-747 satellite sensors, 211 pollutant, 724 Lagrangian, 292 wind profilers, 112 saturated, 91 definition, 292 middle thermo diagram, 100 forecast equations for, 746 clouds (prefix: alto), 162-163, 168 total water, average, 97-99 flux, 375-376 height variation with latitude, 163 total-water, 97, 186 turbulent, 712-713 satellite images of, 234 vs. RH and temp, 92 vs. stress, 712-713 weather-map symbols for, 168, 277 water vapor, 56, 89-98 gradient, 294 European time (MET), 5 weather maps of, 500 length scale, 733 midlatitude, 330 wet-bulb, 94-95 reservoirs, 375 anticyclones, 331, 390-391 in middle of mixed layer, 109-110 specific, 294 cyclones, 331, 425-480 turbulent, effects on frontolysis, 411 transport, 294 Southern Hemisphere, 426 mixture of air parcels, 160-161 by Rossby waves, 375-376 highs, 331, 390-391 MJO (Madden-Julian oscillation), 818, 824 Monin-Obukhov length, 703 lows, 331, 425-480 MKS units (see International System of Units), 7, 870 monochromatic , 36 system collision with hurricanes, 616 irradiance, 36 troughs and ridges, 367-376 ML (see mixed layer) light ray, 833 baroclinic instability and planetary waves, CAPE, 506-507 monodisperse distribution, 197 371-374 moat, 605 monotonic, defined, 9, 290 barotropic instability and Rossby waves, mode of CCN growth, 188 monsoon 367-370 Model Output Statistics (MOS), 770-771 airmass code, 392 heat transport , 374-375 modelers, 751 circulations, 333-334, 343, 356 momentum transport, 375-376 model(s), 751 highs associated with, 333-334, 354, 391, 615 ridge axis, 367 climate, 792 steering hurricanes, 615 weather fog, 173-177 Indian, 356 cloud heights, 163 GCM (Global Climate), 768 trough hurricane trigger, 612 tropopause heights, 163 general circulation, 330-388 Moon, 27 variability, 353, 425-480 heuristic (also see toy models), 280, 330, 793 albedo, 42 midlatitudes, defined, 330 hurricane, 626-629, 637-638 bows, 841 global circulation, 352-355 numerical weather prediction, 751 mass, 28 mid-level vertical velocity, 452-462 current, 751 optical phenomena around, 163 mid-tropospheric fronts, 413-414 history of, 759 orbital period & direction, 27-28, 879 Mie scattering, 857-858 output statistics (MOS), 770-771 Moore, Gordon E., 752 haze, 858 updateable, 771 Moore’s Law, 752 Mie, Gustov, 858 pollution, 725 moral issues of doing science, 218 Milankovitch, Milutin, 797 primitive equation, 747 Morgana, Fata, 862-863 theory, 797-803, 829 sensitivity, 350 morning miles, nautical, 4 toy (simplified), 330 Glory, 656 military , 218 moderate satellite, 229 polar orbiting weather satellite, 273 rainfall rate, 207-208 morphology (shape) of M, N R. STULL • PRACTICAL METEOROLOGY 905

clouds, 168 clouds, 161-169 great scientists and big mistakes, 863 ice crystals, 198-199 cyclones, 425-426 reflecting telescope, 862 MOS (model output statistics), 770-771 hurricanes (tropical cyclones & typhoons), 614- work on colors, 862-863 most-unstable CAPE, 507 615 newton (unit of force), 8, 870 mother retired, 615 Newtonian clouds, 168-169 local winds, 654 physics, 1 Earth (gaia), 813 nano (10–9), 870 transformation, 715 of-pearl clouds, 166 NAO (North Atlantic oscillation), 430, 818-819, 824 Newton’s Law of Gravitation, 11 storm, 485 NAT clouds, 166 gravitational constant, 879 motion National Newton’s Laws of Motion , 1, 292 cyclone translation, 425, 429-431, 433-435 ambient air quality standards (NAAQS), 7, 725 second law, 1, 292, 301, 314-315, 554, 560-561, 670, eddy, 35, 750, 704-716 ambient air quality objectives & guidelines, 725 746-749 equations of, 746-749 Centers for Environmental Prediction (NCEP), Eulerian momentum budget, 293 horizontal, 314 279, 283 Lagrangian momentum budget, 292 equations of, 301-302, 314, 746 Hurricane Center (NHC), 608, 638 in his own words, 292 scales of, 315 Institute of Standards and Technology (NIST), Newtons per square meter, 7, 8 laws, 292 51, 879 NEXRAD (weather surveillance radar WSR-88D), thunderstorm translation, 487, 492, 516-520 Lightning Detection Network (NLDN), 569 243 vertical, 315-320 Oceanic & Atmospheric Admin. (NOAA), 637 locations, 272 boudary layer pumping, 319-320 Weather Service (NWS), 532 nightime (nocturnal) equations of, 315-320, 746 radar used by, 243 boundary layer (stable), 692 in extratropical cyclones, 451-462 natural clouds visible during, 166 in hurricanes, 605, 612, 628-629 climate processes, 793-832 cooling, 690, 692-696 in thermals, 648-649, 694, 703-708, 711-716 cycles & changes in hurricane activity, 631 thunderstorms, 590 in thunderstorms, 482, 485-498, 503-508 greenhouse gas, 811-812 winds (katabatic; mountain; land-breeze), 649- mountain logarithms, base of, 879 657 anabatic (upslope) flow, 649-652 oscillations in climate, 818-824 nimbo prefix, 163 blocking of airmass & high pressure formation, selection, computational, 680 nimbostratus, 162-163 391 wavelength, 666 nimbus suffix, 163 building (orogenesis), 804 nature of convection , 481, 704, 710, 716 NinJo, 772 clouds, 165, 649-650 nautical miles, 4, 870 NIST (National Institute of Standards and Technol- convergence zones, 472 Navier, Claude-Louis, 759 ogy), 51, 879 cyclogenesis (lee), 364-365, 443-446 Navier-Stokes equations, 293, 301-302, 314-317, 759 nitric acid, 190-192, 858 downslope (katabatic) flow, 652-653 NCAR-RIP, 772 trihydrate (NAT) clouds, 166 gap winds, 661-664 NDT, Newfoundland daylight time, 5 nitrogen, 7 high pressure formation near, 391 nebulosis/neb, 168 oxides (NOx), 7, 725, 796, 811-812 katabatic (downslope) flow, 652-653 needed heat transport globally, 338-339 lightning produced, 567 pass winds, 661-664 needle ice crystals, 198-199 nitrogen dioxide, NO2, 7, 725, 858 precipitation, 398-399, 472 neon, Ne, 7 nitrous oxide, N2O, 7, 811 ranges, 397, 661 near NOAA (National Oceanographic and Atmos. Ad- slope infrared and ultraviolet, 222-223 min.), 637 angle, 650-653 source pollutant dispersion, 732 satellites, 229, 273 flows, 649-653 surface (see also surface) weather radio, 529, 638 time zone, 5 global circulation, 330-331 noctilucent clouds, 166 -related clouds, 165 temperature, 330-331 nocturnal triggering of winds, 330-331 boundary layer (stable), 692 easterly waves, 611 Nebeker, Frederik, 781 jet, 311, 699-700 Rossby waves, 364-367, 443-445 negative nodes of satellite orbits, 228-229 thunderstorms, 487, 526 buoyancy, 556 nomenclature (global), 330 upslope feedbacks, 807 nominal plume edge (depth), 730 flow (anabatic), 649-652 flux divergence (=convergence), 64 non-equilibrium wind (at hurricane top), 618-619 rain (orographic), 398-399, 472 polarity lightning, 563-564 nonhydrostatic, 316 wave(s) sign in scientific notation, 870 global circulation components, 351 behavior, 666-668 vorticity advection (NVA), 447-448 hurricane vertical motions, 622, 629 clouds, 165, 667 nested grids (one-way and two-way), 752-753 numerical weather prediction model, 747 drag, 301, 668, 751 net nonlinear Froude number, 668-668 actinometer, 45-47 dynamics high-pressure regions in, 391 Ekman transport, 378, 610, 632-633 and chaos, 773-776 lenticular clouds, 165, 667 evaporation, 92 causing T-storm forecast difficulties, 527 natural wavelength, 666 force, 292-294 forecast equations, 747, 773-776 turbulence, 667 heat budget (Eulerian), 72-73 feedback processes, 806 winds, 649-654, 660-670, 675-676 heating, 72-73, 131-132, 336-339, 465, 546 linear approximation to, 806 movement of longwave flux, 45, 337 nonlocal airmasses, 397 meridional transport of zonal momentum, 375- air-parcel movement, 497-499, 503-508, 557-558, lows (extratropical cyclones), 429-431 376 716 MSL (see mean sea level) pressure tendency, 466-467 closure, 714, 716 pressure, case-study maps, 438 pyranometer, 45-47 conditional instability forecasts for cyclogenesis, 463-467 pyrgeometer, 45-47 for hurricanes, 609 reduction to, 267 pyrheliometer, 45-47 for thunderstorms, 496-499, 503-508 MST, Mountain standard time, defined, 5 radiation, 27, 44-45 flux, 716 Mt. Agung, 805 global distribution, 337-338 stability, 138-139, 142-144 Mt. Fuego, 805 radiometer, 45-47 non-parametric statistics, 502 Mt. Pinatubo, 805 sea level pressure tendency equation, 466 nonstationary flow, 669 MT-SAT, 228 sky transmissivity, 44 nonturbulent (see laminar), 138, 140, 669-671, 688 Mt. Tambora, 805 solar input, 795 nordic ski snow, 209 Muana Loa, 805 spring force, 136 normal MU-CAPE, 507 total water (Eulerian), 107 climate, 818 multicell thunderstorms, 486-487 neutral static stability, 139-140, 688-689 curve (Gaussian), 729-730 multi-field charts, utility of, 443 neutral stability, 138, 140 mode initialization, 766 multiple vortex tornadoes, 592-593 air standard deviations of velocity, 707 shock (1-D) from thunder, 572-574 mushroom cloud (thunderstorm appearance) , 482, boundary-layer wind, 308-310 storm motion, 516-518 532 boundary layers, 688-689 normalized CAPE, 508 determination of, 139-140 Normand’s Rule, 96, 105-106, 500 dispersion within, 733-734 North American geography, 431 drag, turbulent, 701 North Atlantic oscillation (NAO), 430, 818-819, 824 dry, 140 north direction, 2-4, 30, 298-299, 330, 646-647, 797- N plume rise within, 733 802 n-CAPE, 508 saturated, 140 North Pole, 4, 30, 298-299, 330, 646-647, 797-802 NAAQS (national ambient air quality standards), 7, surface-layer wind, 702 north-south (also see meridional), 4, 330 725 neutrally buoyant, 135 displacement of baroclinic wave, 371-376, 452- NACLI code, 269 névé snow, 209 453 nacreous clouds, 166 Newfoundland time zone, 5 temperature gradient (see baroclinicity), 329, names of Newton, Isaac, 292-294, 759, 841, 862-863 334-336, 359, 749 906 INDEX N, O

Northern differencing schemes - spatial, 755 GFS (global forecast system), 751 annular mode (NAM), 824 centered fourth order, 755 heirarchy, 768 Hemisphere, 4, 330 centered second order, 755 WRF (weather research & forecasting), 751 defined, 4 upwind first order, 755 moisture, 746 direction of geostrophic wind, 303, 314 differencing schemes - temporal, 757-758 Moores’ Law vs. NWP skill, 752 sign of Coriolis force, 297-301 Euler (first order), 757 MOS (model output statistics), 770-771 sign of centrifugal force, 296 leapfrog (second order), 757 nests, one-way and two-way, 752 not measured (cloud coverage symbol), 170, 279 Runge-Kutta (4th order), 757 non-linear dynamics and chaos, 773-777 Nova Scotia, 617 discretization, 750 ensemble & probability forecasts, 776-777 novice vs. expert, 72 equations of motion, 758-759 Lorenz strange attractor, 773-775 nowcasting (short-range forecasting), 552, 768 domain, 750 predictability, 773 ns (nimbostratus clouds), 168 dynamics, 749-750 notation for grid points, 754 NST, Newfoundland standard time, defined, 5 economic value, 784-785 nowcasts, 768 nuclear ensemble, 776 numerical stability, 759-761 bomb, 499, 548, 574, 880 calibrated, 777 numerics, 749-750 energy, 54 spread vs. skill, 777 operational short-range vs. GCMs, 816 winter, 151, 805 equations of motion, 746-749 output graphics nucleation, 188 compressible, 747 compression and storage into databases, 772 definition, 185 diagnostic, 747 graphics, 772 deposition, 194-195 discritized, 758-759 parameterizations (numerics), 749-751 freezing, 194-195 non-hydrostatic, 747 perfect prog method (PPM), 770 heterogeneous, 188-194 primitive, 747 persistence skill, 780 homogeneous, 188-194 prognostic, 747 physics, 749-751 ice crystals, 194-196 errors subgrid-scale, 750 nuclei, 194-195 bugs in the code, 759 post-processing, 762, 770-772 processes, 198-201 dynamic instability, 759, 773-777 predictability limit, 773-776 liquid droplets, 188-194 numerical, 759-761 probabilistic, 777 activated nuclei, 193 numerical instability, 760-761 calibrated, 777 cloud condensation nuclei (CCN), 188 random, 777 verification, 782-784 critical radius, 192 round-off, 759 process, 762-772 curvature and solute effects, 189-191 systematic, 770, 777 balanced mass and flow fields, 763-764 haze, 192 truncation, 754-755, 760 case study, 768-769 nuclei (see also cloud condensation nuclei, CCN), verification & error measures, 777-785 data assimilation and analysis, 764-767 188-195 viruses, 759 forecast refinement, 770-771 number, 870 file formats for output, 772 forecasts, 768 Ball ratio, 698 finite-difference equations, 754-759 post-processing, 770-772 density of applications to spatial gradients, 754-755 quality CCN, 187 differencing schemes of various orders, 755 control of input data, 765 hydrometeors, 187 notation, 754 of forecast, 777-785 ice nuclei, 195-196 spatial differencing, 754-755 quite revolution, 772 Froude number, 659, 667 Taylor series, 754-755 resolution, 750, 752, 761 hydrometers, 187 time differencing, 757-758 vs. grid spacing, 761 Mach, 571-576, 579, 674 truncation vs. order of terms, 754-755 scale vs. skill, 768 prefixes, 870 finite-volume model, version 3 (FV3), 751 schedule, 762 Richardson, 141, 521, 709-710, 739 first guess, 765-767 scientific basis for, 746-751 Rossby, 306, 313 flops (floating point operations per second), 761 seasonal forecasts, 768 scientific notation for, 870 forecast quality, 780 semi-Lagrangian, 761 swirl ratio, 592 accuracy vs. skill, 777 sensitive dependence to initial conditions, 773- value, 870 verification scores, 777-785 776 numerical forecast refinement, 770-771 short-range forecasts, 768 approximations to eqs. of motion, 749-750 forecast stage of NWP, 768 skill, 772, 777-784 instability, 759-761 GCMS (global climate models -or-), 768, 815-816 vs. forecast time, 775, 780 model (see num. weather pred. model), 496, 751 (general circulation models), 768 vs. scale, 768 parameterizations (numerics), 749-751 governing equations (see eqs of motion), 746-750 solutions to atmospheric equations, 749 problems, explained, 21 GPUs, 763 spatial gradients, approximations, 754-755 solutions to atmospheric equations, 749 graphical outputs, 772 spread (of ensembles) vs. skill, 777 stability, 759-761 grid staggered grids, 753 value, 870 A - E, Arakawa, 753 statistics, 777-785 numerical forecast models (see numerical weather cells, 750 stencil, 756 prediction) computation rules, 756 strange attractors, 773-776 numerical weather prediction (NWP), 745-792 cubed sphere, 752 temperature, 746 accuracy, 777 nested, 752 temporal gradients, approximations, 757-758 Amdahl’s Law vs. NWP speed-up, 763 notation, 754 thunderstorm sounding forecasts, 496 analysis/assimilation of data, 762, 765-767 points, 749, 752-753, 761 time steps, 750, 761 verifying, 769 resolution, 752 uncertainty in the forecast, 776 Arakawa grids A to E, 753 spacing, 761 valid time, 762 backward trajectory for semi-Lagrangian, 761 staggered, 753 verification statistics, 777-785 balanced mass and flow fields, 763-765 variable, 752 visualization programs, 772 blowing up of solution, 757 heirarchy of operational forecast models, 768 winds, 746 boundary conditions, 756 hindcasts, 762 numerics, in numerical weather prediction models, ghost cell or halo grid points, 756 history, early, 759 749-750 calculation of secondary variables, 771-772 human contributions to the forecast, 772 NVA (negative vorticity advection), 447-448 calibrated probabilistic forecasts, 777 initial conditions, 758, 762 NWP (see numerical weather prediction), 745-792 case study, 768-770 sensitive dependence, 773-776 climate, 768, 815-816 synoptic vs. asynoptic data, 758 climatology (as a skill reference), 780 initial value problem, 762 computation rules, 756 initialization of NWP models, 763 confidence in the forecast, 776 instabilities O coordinate systems, 746-748 dynamic, 773-777 O2, oxygen, 7 cubed sphere, 752 numerical, 759-761 O3, ozone, 7 eta, 746 lead time, 762 oasis effect, 74 hyrid, 746 limit of predictability, 773-776 object immersed in a fluid, 135 polar stereographic, 747 Lipschitz condition/continuity, 761 objective analysis method, 280, 766-767 sigma, 746 long-range forecasts, 768 objective optimum interpolation analysis, 766 spherical, 747 Lorenz, 773-776 oblate terrain-following, 746, 753 map rain drop shape, 255-257 corollaries, 756, 758 factors, 747 spheriod of revolution (Earth is), 3 cost/loss decisions, 784-785 output graphics, 772 obliquity, Earth axis tilt, 30, 879 Courant number, 758 projections, 748 variations and climate, 798-803 cubed sphere grid, 752 medium-range forecasts, 768 obscuration, weather map symbols, 276 data assimilation and analysis, 765-767 meteograms, 745, 772 obscured sky, 170, 279 design, 761 models, 496, 751 observations deterministic, 777 GEM (global environ. multiscale), 751 errors, 766, 875-877 O, P R. STULL • PRACTICAL METEOROLOGY 907

locations worldwide, 271-273 polar orbiting satellite, 227-228 Pangea, Pangaea, Pangæa, 388, 804 reporting, 875 satellite, 227-229 pannus, 169 synoptic, 268 orbital factors of Earth, 27-34 Papa, Station, 288 weather, 268-273 climate variability, 797-803, 829 paradigm shift, 773, 863 observers of atmospheric optics, 833-868 daily effects, 32 paradox, geostrophic, 459, 462 observing system simulation experiment (OSSE), Milankovitch theory, 797-803, 829 parallel damage paths, 584 236 orbit of earth, 27 parallels, defined, 4, 330 Obukhov length, L, 703 period of satellites, 227-229 parameterization, 715 Occam, William of, 680 seasonal effects, 30 and models, 751, 816 Occam’s Razor, 680 sunrise, sunset, and twilight, 33 physical and numerical, 750-751 occluded fronts, 413-414, 428-429 orbital period of planets, 27-28, 872 rules, 715 weather-map symbol for, 281, 399 orbital plane, 30-31, 799-802 turbulence closure, 714-716 trough of warm air aloft (TROWAL), 281, 399 ordinate (defined; and use of pressure as), 3 parameters, 646, 669, 715, 750 occluding low, 428 organization of combined, 880 at landfall in Pacific Northwest , 472 clouds, 167 physical, 879-880 occlusion process, 428-429 thunderstorms, 486-495 paranthelia, 854-855 ocean organized convection in tropical disturbance, 613 parcel (see also air parcel), 57, 59 aerosols and CCN over, 188 organizing knowledge, 72 lapse rate (see also lapse rate), 59-64 CO2 orientation of falling ice crystals, 842, 855 method to determine stability, 138-139 effervescence, 812 origin of tornadic rotation, 586-587 vs. environment (on thermo diagram), 134 feedback process for climate, 810-812 orogenesis (mountain building), 804 parhelia (sun dogs), 842, 850-851, 854-855 continent circulations (monsoons), 333-334, 356 orographic (related to mountains) 120°, 854-855 circulations, 804 cloud, 165, 168, 676-677 sub, 842, 851, 854-855 meridional overturning, 810 high-pressure formation near, 391 parhelic circle , 842, 844, 854-855 thermohaline, 804 lee-side cyclogenesis, 443-446 Parry currents, 431, 610, 632-633, 701 lift and cloud formation, 162 arcs, 854-855 Gulf Stream, 431 precipitation modifying airmasses, 398-399 oriented ice-crystal columns, 855 heat transport by, 339, 378 thunderstorms, 487, 526, 547-548 partial hurricane-induced, 610 winds, 649-654, 660-670, 675-676 absorption, 220-223 Kuroshio, 431 oscillation(s), 136-137 density, 91 wind-driven, 701 amplitude, 818 pressure, 14, 87, 115 divergence of ocean water, 610 climate, natural, 818-824 weather-map symbol for, 276 drag, 701 damped, 666 particles in air, 188, 725 Ekman inertial, 304, 311-312, 700 particulate matter (air pollution) spiral, 378 period, 137, 304, 818 fine (PM10), 725 transport, 610 phase shift, 818 very fine (PM2.5), 725 meridional overturning circulation, 810 TRUE, 818 volcanic eruptions, from, 804-805 methane hydrate release, 810 waves parts of wind: mean, waves, turbulence, 705 mixed layer, 610 mountain lee, 666-668 parts per billion (ppb), 724 storm surge, 632-635 Rossby, 367-376 parts per million (ppm), 724 surf, 635 what is an oscillation, 818 pascals (Pa), unit of pressure and stress, 7, 8, 870 thermocline, 610 out of phase light waves, causing interference, 858- Pasquill-Gifford (PG) turbulence types, 727-728 thermohaline, 804 861 pass, winds through mountain gap, 661-664 upwelling during hurricane, 610 outbreaks of tornadoes, 583-584 passat (trade) inversion, 351 waves during hurricane, 633-636 outer space, 234 passion, scientists should have, 877 odor characteristics of airmasses, 391 outflow winds from thunderstorm, 483, 554, 560-563 passive ohm, unit of electrical resistance, 564-565, 870 clouds, 163 oktas, 170, 279 outgoing microwave sensors of rain, 211 Olympic Mountain convergence zone, 472 radiation, 337 sensors, 219 omega (vertical velocity in P coordinates), 451 radiation from opaque atmosphere, 220 tracers, 731 equation, 456-459, 462 radiative flux, 337 past weather, as plotted on weather maps, 275 Q-vector, 462 terrestrial radiation, 337 patchy, weather-map symbol for, 276 Sutcliffe development theorem, 456 transmitted radiative flux, 220-223 path length, Beer’s Law, 43 Trenberth, 456-458 outlier data points, 502 path of shape of setting sun, 862 outlook forecasts of severe weather, 528-530 radar beam, 243-245 one-layer atmosphere, 795 overcast (ovc) cloud cover, 170, 279 Rossby wave, 368-374 one-way nesting of NWP grids, 752 over-pressure from thunder shock front, 571-574 patterns, 107 Oort minimum in solar activity, 803 over-riding air at fronts, 407 dominant pattern finding via PCA, 821-823 opacus, 169 (of thunderstorm), 483, 498, 508 Pauling, Linus, 99 opaque oxides of nitrogen (also see nitrogen oxides), 193 PCA (principal component analysis) method, 820- atmosphere, 220 oxygen, O2, 7, 723 823 surface, 42 ozone, O3, 7, 193 PDO (Pacific Decadal Oscillation), 818-820 open air-quality standards for, 725 PDT, Pacific daylight time, defined, 5, 6 cellular convective clouds, 167 greenhouse gas, 811-812 peak current in lightning, 568-569 channel hydraulics, 657-661 lightning produced, 567 Peel, 817 operational numerical weather forecast models odor, 567 Peirce’s skill score, 781 (OFMs), 751 tropopause folds, injection at, 364 pellets, ice (sleet), 199, 276 heirarchy, 758 snow (graupel), 199, 276, 546 opposite faces of ice crystal, 842 pendulum day, 304, 312 optical penetrative convection, 483, 498, 508 depth, 43, 856 pennant wind-speed symbol on weather maps, 278 due to volcanic eruptions, 805, 858 P percentiles, 502 hygrometer, 111 P (Newfoundland time zone) defined, 5 perfect prog method (PPM), 770-771 thickness, 43, 856 Pacific, 431 perihelion, Earth orbit transient (lightning) detectors, satellite borne, airmass modification, 398-399 angle relative to vernal equinox, 34, 801 569 data void, 287-288, 765 climatic variation, 799-801 optically thick fog, 176-177 decadal oscillation (PDO), 818-820 Earth orbit, 28-30 optics, atmospheric, 833-868 high, 356 period arcs, 847-855 landfalling cyclones, 472 earth and moon rotation, 879 diffraction & interference, 858-860 North American pattern (PNA), 824 of oscillation, 137, 818 halos, 842-855 Northwest of satellite orbits, 227-229 ice crystal, 396, 842-855 geography & topography, 661 Quaternary, 799 liquid droplets, 837-841 weather, 288, 397-399, 472, 765 perlucidus, 169 mirages, 861-863 oscillations in climate, 818-824 permafrost, 810 scattering, 856-858 South Pacific subtropical high, 354 Permian-Triassic boundary, 805 optimistic probabilistic forecast scores, 785 time zone, defined, 5 permittivity of free space, 569 optimium tropical cyclones, 631 persistence forecast, 778 interpolation analysis, 766 packing of error, 778 wind-speed decrease in wind turbine, 647-648 height contours, 290-291 skill, 780 orange color defined (also see optics chapter), 37 isentropes & relationship to stability, 143 personal errors, 875 orbit isobars, 290-291, 307 perspiration, 76 geostationary satellite, 227 PAH (polycyclic aromatic hydrocarbons), 725 Persson, Anders, 298 planetary, 28, 293 paleotemperature estimates, 795, 803 perturbation pressure, 340-341, 554, 559-563 908 INDEX P pessimistic probability forecast scores, 785 typical wavelength, 367 732 peta (1015), 870 planets in the solar system, data for, 22, 27, 874 Gaussian concentration distribution, 729- Watt, 339 plan-position indicator (PPI), 242 730 PG (Pasquill-Gifford) turbulence type, 728 plant canopy, 677-678 plume rise, 732 phase plasma, 565 dispersion in unstable boundary layers, 735-737 change, 56 plateaus, 397 concentration, 737 condensation, 56 plates, ice crystal, 198-199, 842 crosswind integrated concentration, 736 deposition, 56 optics caused by, 842-855 plume centerline, 736 fusion, 56 Platzman, George, 759 relevant variables, 735-736 melting, 56 Pleistocene epoch, 799 dispersion statistics, 728-730 sublimation, 56 plotting center of mass, 729 vaporization, 56 by hand, 280-281 Gaussian curve, 729-730 water, 54 station model, 274-279 nominal plume edge, 730 diagram for weather maps, 280-281 snapshot vs. average, 728 attractors and strange attractors, 774, 790 winds, 210-513 standard deviation - sigma, 729-730 water, 198 plume episodes, events, exceedences, 725 shift, 250-251 average, 728 footprint, 733 in high-pressure regions, 390-391 center of mass, 729 framework: source-receptor, 724 of deterministic oscillations, 818 centerline, 723, 729, 736 Gaussian concentration distribution, 729-730 space, 774, 790 centerline height, 723, 733-734, 736 in highs and airmasses, 390, 691 specific differential, 256-257 concentration, crosswind-integrated, 737 in lows, 691 speed coning, 727 mixing ratio, 724 of Rossby wave, 369 convective, 724 modeling, 725 intrinsic, 369 definition, 724 passive, 731 relative to ground, 369-372 dispersion, 723-744 point source, 724 shallow-water, 633, 658 edge, nominal, 730 smoke stack, 724 space plot (“butterfly”), 774-775 fanning, 727 solution, 724 warm and cool (of ENSO and PDO), 818-820 footprint, 734 source phased-array radar, 257-258 Gaussian concentration distribution, 729-730 height, 723 phases of water, 198 instantaneous (snapshot), 728 receptor framework, 724 phenomena, optical, 833-868 looping, 727 spread of pollutants, 729 philosophers, 2 rise, 648-649, 723-724, 732-737 stack height, 723 philosophy of science, 877 smoke, 723-744 standards for air quality, 725 phloroglucinol, 195 spread, 723-744 Taylor’s statistical theory, 731-732 photo-detector in dew-point hygrometer, 111 thermal, 648-649, 654, 704, 724 dispersion equation, 731-732 photoelectric effect, 46 urban, 679, 743 dispersion near and far from source, 732 photographic tips, clouds, 180, 484 PM (particulate matter) air pollutants, 725 passive conservative tracers, 731 photometer, 46 2.5 (very fine particulates, air pollution), 725 trapping, 390 photons, 833 10 (fine particulates, air pollution), 725 in valleys, 654 photoresistor, 46 PMC (), 166 turbulence statistics, 726-728 photovoltaic cells (solar cells), 46 POES satellites, 229 Pasquill-Gifford (PG) turbulence types, 727- physical point source, 724 728 meteorology, 1 polar, 330 pool of cold air, 653 parameterization (physics), 749-751 airmass code, 392 population vs. physics cell , 329, 332-333, 352, 357, 378 air pollution, 723 atmospheric, 872 cloud heights, 163 hurricane disasters, 631 parameterizations in NWP models, 749-751 coordinate, 2, 646 urban heat-island temperature excess, 679 Newtonian, 1 cyclones, 425 portion phytoplankton, 188, 811 easterlies, 352 correct, 781 pi (π = 3.1415926535897932384626), 879 front, 352, 357, 367, 408 of forecasts corect, 781 variant, 801 graph used as a hodograph, 510-513 positive pico (10–12), 870 heat deficit, 338-339 feedback, 807 pileus clouds, 165-166, 169, 483 highs (anticyclones), 331, 352, 391 polarity lightning, 563-564 pillar (sun, moon, Venus, street light), 843 jet stream, 233, 331-332, 353, 357-360 vorticity advection (PVA), 447-448 pillow, snow, 210 low, 332 post-processing of numerical forecast, 762, 770-772 PILOT code, 269, 272 mesospheric clouds (PMC), 166 postal abbreviations for US states & Canadian prov- MOBIL, 269 orbiting satellites, 227-229 inces, 431 SHIP, 269 regions, 330 potential pilot balloons (PIBALs), 272, 322 stereographic map projection, 748 breakdown lightning, 566 pilots - weather issues, 165, 166 stratospheric clouds (PSC), 166 difference, electrical, 564 altimeter setting, 275 tropopause height, 163 energy, 150 METAR weather reports, 268-279 upper-tropospheric low, 352 associated with horizontal temperature gra- Pinatubo, Mt., volcanic eruption, 805 vortex, 352, 397, 824 dient, 406 pineapple express, 472, 824 polarity of lightning, 563-564 convective available (CAPE), 503-508, 530- piste, 209 polarimetric radar, 241, 255-257 531 pitfalls, scientific, 877 dual polarization, 255 of flow, 669-672 pitot tube, 321, 674 polarization diversity, 255 temperature, 61-64 pitot-static pressure difference for air speed, 674 polarization(s) constant (see adiabatic or isentropic), 61-64 plagiarism, 24 circular, 255 definition, 61 Planck horizontal, 255-257 diurnal evolution, 690-698 constant, 879 vertical, 255-257 equivalent, 104-106, 500 curve, 36-39, 224 polarized light, 856-857 in atmospheric boundary layer, 689-698 function, linear approximations to, 239 polarizing sunglasses, or filters for cameras, 856 in buoyancy, 136 Planck’s Law, 36-38, 221-224 Poles (North & South), 4 in vertical cross section of front, 403, 405, constants, 879 poleward transport of heat and momentum, 374-376 407-409, 414 plane angle, dimension and units, 870 isentrope, 17-18, 63, 103-105, 122-123, 143-144, planetary police radar, 243 156, 365, 373, 403, 407-410, 414, 437, 624- boundary layer (see atmospheric boundary lay- pollen characteristics of airmasses, 391 625 er), 13 pollution/pollutants, 7, 725 liquid water, 103-106, 500 data, 22, 47 air quality standards, 7, 725 maps of constant, 437, 443 orbits, 27, 293, 874 airmass characteristics, 391 mixed layer, 689-698 scale, 315 brown cloud, 857-858 on weather maps, 437-438, 441 general circulation, 329-388 concentration units, 724 profile in boundary layer, 110, 690, 692, 695- shear, 368 ppmm, 724 698 vorticity, 363-364, 367-372, 447-449 ppmv, 724 substitute for advection, 67 wavelength, 329, 367-376, 427, 468 µg/m3, 724 thermo diagram, 135-136 waves (also see Rossby waves), 367-376 conservative, 731 vertical profile, 135-136, 689-698 definition, 367 conversion between units, 724 virtual, 61-62 highs associated with, 391 crosswind-integrated concentration, 735-737 vs. height, 61-63, 104-106 horizontal, midlatitude, 367-376 dispersion, 723-744 wet-bulb, 103-106, 500 path taken, 372-374 factors, 724-725 vorticity, 363-364 phase speed, 369, 372 forecast equations, 731-732 conservation of, 363-365, 397, 445 stationary (lee side), 443-444 dispersion in neutral & stable boundary-layers, isentropic, 364-365 P R. STULL • PRACTICAL METEOROLOGY 909

units (PVU) definition and maps of, 364, 437, jet, 407, 433, 472 net, 466-467 441 pineapple express, 472 rainfall-rate relationships for, 465-467 pounds-force per square inch, pressure units, 7 waves, 656 weather-map symbols for, 277-278 powder snow, 209 present tendency equation, 463-467 power climate, 816-817 thermo diagram, 63, 100, 103-106, 119-131, 151- curve for wind turbines, 648 weather, as plotted on weather maps, 275-276 158 dimension of, 870 pressure, 8-10, thunder, 571-574 electrical by wind turbines, 647-648 background state, 316 tiling method for CAPE, 505 electricity, 564 change with height, 8-9, 316 tornado, core, 577-578 flashes, 584 monotonic, 9 trough, 367-376, 399, 432-433, 443 lines, electrical surges caused by lightning, 569- weather-map symbols for, 277-278 units, 7, 870 570 charts, 436-442 vapor, 87 of hurricanes, 620, 625 constant, 17, 55-56, 290, 439-441 saturation, 87-90 of lightning electricity, 569 cooker, 115 vertical gradient, 8, 9 output curve for wind turbines, 647-648 coordinates, 290-291, 451 in hurricane, 622 relationships on log-log graphs, 874 couplets, non-hydrostatic, 340-341 pre-storm environments, 496-527 surge by lightning, 569-570 deepening, 463 prevailing visibility (in METAR), 270 units, 870 deficit in tornado, 577 primary rainbow , 838-840 PPI radar scans, 242 definition, 7, 870 prime meridian, 4, 5, 28 ppm (parts per million), 724 difference, as indicates mass of air, 10 primed variables, 368-376, 705-716, 726-729 (perfect prog method), 770 dimension of, 870 primitive equations of motion (see also equations), praecipitatio, 169 distribution in hurricane, 626 747 Prandtl mixing length theory, 715 driving the global circulation, 340-342 vs. quasi-geostrophic equations, 449 precession of dynamic, 559, 672-674 principal component Earth’s orbit, 28, 798-803 errors, 766 analysis (PCA) method, 820-823 aphelion, 800 evolution, for MSL, 467 of Pacific Decadal and Arctic Oscillations, 819- axial, 800 falls, 463 820, 824 climate, 801 field, 343, 359 Principle, Le Chatelier’s, 132, 141, 329 equinox, 800-801 filling, 463 principles of radiation, 36 satellite orbits around Earth, 229 free stream, 672-674 prism precipitable water , 98-99, 501, 546 forecast equation for, at MSL, 463-467 face, 842 on weather maps, 501 global patterns, 331, 350-355 shaped ice crystals, 199, 842 precipitating clouds, 163 gradient, 295-296 probabilistic forecasts, 777 precipitation, 185-218 horizontal, 295-296, 559-561 calibrated, 777 accumulation gradient force, 295-296, 301 cumulative, 777 isohyet, 18 cross-mountain, 662 scores, usage of, 785 weather-map symbols for, 278 horizontal, for anabatic flow, 650-652 verification, 782-784 amount, 18, 107-108 near center of pressure region, 306-307 probability annual distribution worldwide, 209 on isobaric surfaces, 296 forecasts of hurricane threat, 638 characteristics, 207-210 related to packing of isobars, 303 of detection, 781 cloudless ice sign convention, 295-296 wind speed, 645-646 cold-cloud process, 201-202, 206 winds driven by, 302 vs. relative frequency, 645 distribution worldwide, 209 vertical, 15-16, 18, 315-317, 554 problem-solving methods, 72, 869 drag, 555 head, 632 forward, 236 efficiency of thunderstorms, 547 height inverse, 236-239 extreme, 207-208, 545-548 as vertical axis on graphs, 9-10, process(es) fog, 173 increments, 103 adiabatic, 17, 60 formation, 205-207 tendency, 463 causing saturation, 159-161 growth, 202-207 high (anticyclone), 354-355, 390-391 cold cloud, 201, 205-206 hail, 548-554 meso-, 554, 559-563 cooling, 44-45, 59-76, 129-133, 393-397, 693, 793- heavy rain, 207-208, 545-548 hurricane, 621-623, 626, 633 797 ice, from arctic airmasses, 396 hydrostatic balance, 15-16, 316, 340, 622 diabatic, 61, 411, 465, 624, 648-657 in water budget, 107-108, 746 hypsometric equation, 16-17 isobaric, 17, 55 intensity, duration, frequency (IDF), 208 in eye of hurricane, 618-620, 622, 624, 626, 629, isohume, 100-101 laden air, unsaturated, 555 632-633 isothermal, 100 likelihood or probability (POP), 782-784 instruments for measuring, 19 lapse rate, 59 loading of air, 555, 559 isallobar, 18 names, 17 measurement, 210-211 isobar, isobaric, 18 nucleation of ice crystals, 194 METAR code, 208 isotropic nature, 8 saturation causing, 159-161 midlatitude cyclones, associated with, 425-428, latent heating causing falls of, 466-467 terminology, 17 435, 438, 466, 472 lightning, 564 thermo diagrams, 100-101 on thermo diagrams, 121, 130-131 maps on surfaces of constant, 436-442 warm cloud, 204-205 orographic, 398-399, 676-677 mass of air above, 10, 464-466 WBF (Wegener-Bergeron-Findeisen), 201 parameterization in NWP models, 751 mean background state, 316 profile, vertical radar, 486 meso-high, 554, 559-563 of pressure, 8, 9 rate, 107-108, 207-208 mesoscale variations in thunderstorms, 488-489, profilers as affects cyclone evolution, 465-467 554-563 computer code, 763 and latent heating of an air column, 465-467 METAR, 270 wind, 112 return period (IDF), 208 non-hydrostatic couplets, 340-341, 622 prognostic equations (also see numerical weather snow fall, 131 observation errors, 267, 766 fcst), 747 symbols on weather maps, 208, 275-276 omega, 451 projections terminal velocity, 202-204 on weather maps, 275 map, 748 thunderstorm, 206-207, 482, 486, 545-548 partial, 87 vector or info, 239 intensity forecasting using n-CAPE, 508 perturbation propagation time for start or end, weather map symbols, 278 buoyancy force, 555 anomalous, 244 unknown type (weather-map symbol for), 276 downburst and gustfront, 554, 559-563 equation for radar beam, 244 visibility within, 208-209 profile in the vertical, 8-9, 340-342 of cold fronts (using Q-vectors), 470-471 vs. evaporation, 210 reduction to sea level, 267 of errors through equations, 876-877 warm-cloud processes, 204-206 reversal in hurricane, 618-623 of radar beam path, 243-245 water equivalent, 208 rises, 463 of radiaion, 36 WBF process, 201-202 scale height, 8 of thunderstorms, 485, 561 weather-map symbols, 275-276 sea level, 7 propellor anemometer, 321 zonal average, 210 reduction method, 267 prop-vane anemometer (propellor), 321 precision and random errors, 875-877 sensors, 19 provinces in Canada, 431 predictability shock front, 571-574 proximity symbols on weather maps, 276 limit, 773 stagnation, 672-674 proxy measures of climate information, 803 nonlinear dynamics & chaos, 773-776 standard, 7 pseudoadiabatic diagrams, 121-123, 126-127, 153 predicting (see forecasting; STP, 7, 107, 880 PSI, pounds-force per square inch, pressure unit, 7 or numerical weather prediction), 745-792 static, 7, 559, 672-674 PST, Pacific standard time, defined, 5 predictands, 770 tendency psychrometer, 111 predictors, 770 cyclogenesis, 463-467 aspirated, 94, 111 prefix component of scientific notation, 870 forecast equation for, 463-467 sling, 94, 111 prefrontal isallobar, 18 psychrometric 910 INDEX P, Q, R

constant, 75, 108, 880 hook echo, 494 793-797 graphs, 95 humidity measurement using, 112 exitance, 36 tables, 95-96 hurricane images, 604-605 flux publish or perish, 863 image interpretation, 253-254, 491 gradient, 71 Puget Sound convergence zone, 472 insect returns, 248-249, 560 net at surface, 45, 74, 336-339, 528, 693-694, pulse klystron tubes, 240 793-797, 801-803, 807-815 duration & length, radar, 240 laser (lidar), 112 fog, 173-177 repetition frequency (PRF) of radar, 240 loop, 241 forcings, 329, 334-339 thunderstorm, 486 magnetron tubes, 240 by latitude belt, 338-339 pumping, boundary layer, 319-320 max unambiguous range (MUR), 240-241, 251 climate-change, 793-815 PVA (positive vorticity advection), 447-448 max unambiguous velocity , 250-251 incoming solar (insolation), 336-337 PVU (potential vorticity units), 364 NEXRAD WSR-88D radar (in USA), 240-243 net, 337-338 tropopause identification, 364 plan-position indicator (PPI), 242 outgoing terrestrial, 337 example on weather map, 364, 441 phased array, 257 zonally integrated, 338-339 pyramid polarimetric, 241, 255-256 frontal effects, 411 face, 842 power, 240, 245 global ice-crystal optics/halos, 847 precipitation observation, 211 albedo, 793 pyranometer, 45-47, 219 pulse climate equilibrium, 794, 806-815 pyrgeometer, 46-47 duration, 240 forcings, 329, 334-339, 793-797 pyrheliometer, 46-47 length, 240 heating, 70, 687 repetition frequency (PRF), 240, 250 incoming, 793, 797 radome, 253 infrared (longwave), 27, 37 rainfall rate measurement, 211, 247, 257 insolation, 40-41, 336-337, 797, 801-802 range instruments for measuring, 45-47 Q height indicator (RHI), 242 inverse square law, 39-41, 245-246, 801 Q time zone (Atlantic), defined, 5 measurement, 240-241 irradiance, 36 Q-vectors, 460-462, 469-471 reflectivity (the name for scattered energy), 245- longwave (or terrestrial or IR), 37, 131, 793-794 cold-front propagation, 470-471 248 net, at surface, 27, 797 convergence, 460-462, 469-471 equation for, 245-246 outgoing, 794 cyclone propagation, 469-470 factor, 245-246 parameterizations in NWP models, 751 frontal intensification & propagation, 469-471 isoecho, 18 principles, 36-45 omega equation, 462 returns, 240 absorption, reflection & transmission, 36 vertical velocity & cyclogenesis, 460-462 S band, 242 average daily insolation, 40 weather maps, case study cyclone, 461-462 sample volume, 240 Beer’s Law, 43 quadrants of jet streak, 454-456 scans, 241-242 blackbody emission, 36-38 quality-control, 765 shadows, 241 distribution, 39-40 quality of spectrum width, 254 emission definition, 36-37 air, 725 standard refraction of beam, 244 emission temperature of Earth, 37 forecasts, 777-786 thunderstorm images & diagrams, 482-483, 486- emissivity (IR) table, 42 life, 723 488, 490-493, 532, 560 propagation, 36 quantiles, 502 right- and left-moving supercells, 519 Stefan-Boltzmann Law, 37 quartiles and interquartile range, 502 tornado vortex signature (TVS), 251, 253 transmittance windows, 43 quasi- volume scans, 241, 249-254, 493 Wien’s Law, 37 biennial oscillation (QBO), 824 wind profilers, 257 rain drop growth affected by, 206 decadal oscillation (QDO), 824 WSR-88D weather surveillance radar, 240-243 sensors, 45-47 stationary front (surface & aloft), 281, 399 Z-R relationships, 247 solar (shortwave), 37, 793 quasi-geostrophic, 449 radial constant (total solar irradiance), 793 approximation, 449-451 component, 249 up/downwelling, 44, 131-132 vorticity, 449-451 distance, 240-241, 296-301, 304-314, 319, 362-371, terrestrial (longwave or IR), 37 equation for, 449 453, 511-513, 560-562, 571-574, 577-578, thermo diagram process, 131-132 Laplacian form, 450 617-618, 622-623, 626-630, 837-855, 861 warming of air, 71-73, 795-797 quaternary radar-, 242, 249 windows, 43, 220-223, 796, 811 period, 799 shear, 362-364 radiative transfer equation, 224-225, 237-238 rainbow, 840 velocity, 249-254, 310, 318, 321, 560-562, 572-574, forward problem, 236 627-628 inverse problem, 236-239 wind in hurricane, 627-628 radiatus, 169 wind speed, 18 radio isodop, 18 acoustic sounding system, 78, 266, 272 R radian, unit of plane angle, 870, 880 detection and ranging (radar), 219 r (correlation coefficient), 779 radiance NOAA weather, 529, 638 R time zone (Eastern), defined, 5 blackbody, 221-226 severe weather reporting, 529-532 radar , 219, 240-260 from atmospheric layers, 224-225 radioactive decay, 364 antenna, 250 locations of satellite observations, 273 radioactivity characteristics of airmasses, 391 AVCS display, 242 radiant energy (see also radiation) radiometers, 45-47 bands (electromagnetic), 223, 242 radiant exitance (emittance), 36 satellite borne, 220 beam, 240 radiation, radiative, 27-52 radionuclide injection at tropopause folds, 364 propagation equation, 244 absorption in clouds, 131-132 radiosondes (also see rawinsonde), 111, 134, 143, 291 propagation paths, 243-245 airmass genesis, role in, 393-397 width, 240 average annual, 336-337 radius bounded weak echo region (BWER), 552-553 average daily insolation, 40-41, 336 critical, 192 bow echo, 491 balance, 43 deformation, Rossby bright band, 248 of the whole Earth, 793-797 external, 405-406 C band, 242 blackbody, 36, 794 internal, 319-320, 344 CAPPI display, 242 budget, 42 droplet, 187, 202-204 defined, 219 global, 793-797 Earth, 879 difficulties, 254 surface, 44 earth orbit, 879 Doppler, 241, 249-254, 493, 556, 560 climate-change issues, 806-815 equivalent, droplet, 203 downburst observations, 560 cloud processes, 131-132 hydrometeor, 187 ducting and trapping, 244-245 constants in Plancks’s law, 36, 221, 879 of curvature, 445 echo intensity, 240 cooling / heating, 131 of light rays in mirages, 861-863 inside thunderstorms, 486, 560 front strengthening, 411 in jet stream, 367-373 isoecho, 18 of hurricane top, 624-625 lee cyclogenesis, 445 weather maps, 438 of well-mixed fog, 175-177 of planets in the solar system, 22 echo-free vault, 552-553 daisyworld, 813-815 radix layer, 700-705 energy differential heating, 329, 334-339 radome, 253 attenuation, 241 distribution, 39 RADOB code, 269 scattered (reflected) back, 240-241 downwelling, 43-44 RADOF code, 269 equation, 245-246 Earth-atmosphere system, 793-797 RADREP code, 269 derivation of, 245 effect on circulation, 377 rain (also see precipitation), 185-218, 482-484 false echo, 251 emission accumulation, storm total, 257 fundamentals, 240-244 emissivity, 36 weather map symbols for, 278 gust front observations, 560 temperature, effective, 794 acid, 742 hail observations, 247-248, 552-553 equilibrium of whole Earth-atmosphere system, bands R R. STULL • PRACTICAL METEOROLOGY 911

at warm fronts, 401 flow classification, 659 table of,, 42 in tropical depressions & hurricanes, 604- RASS (Radio acoustic sounding systems), 78, 266, unit factor for radar, 245-246 605, 613-615 272 refract clouds rate radar beam, 244-245 cumuliform, 162-163 of buoyant production/consumption of TKE, refraction, 833-855 stratiform, 164 709 atmospheric, 861-863 drop of molecular diffusion, 196-202 light, 33, 833 shape, 203, 545-546 of earth’s rotation, 227, 297-299 components in 3-D, 836 size distribution, 207 of growth of mixed layer, 697-698 refractive index, 834-835 velocity, 203 rated wind speed for turbines, 648 for radar, 243-244 evaporating (virga), 482-484 ratio Snell’s Law, 575-576, 834-837 gauges, 98, 210-211, 219 Bowen, 74-76 sound waves, 575-576 heavy, 207-208, 545-548, 637 of gas constants, 91, 880 standard (for radar beams), 244 hurricane, 604-605, 607, 637 raw data, 765 sub-, 244-245 IDF (intensity, duration, frequency), 208 rawinsonde (radiosonde) , 134, 272 sunrise & sunset effects, 33, 862 in tropics, 209 balloon, 322, 496 super-, 244-245 intensity, duration, frequency (IDF), 208 code for reporting (TEMP), 269-271 refractive index, 834-835, 861 leaving an air parcel, 130-131 data, 134 light, through air, ice, and water, 834-835, 861, mid-latitude thunderstorm, 206 frontal structure using, 403 880 orographic (upslope), 472 mandatory levels, 134, 772 magnitude of radar targets, 245-246 scattered showers, 545-546 significant levels, 134, 147 radar, 243-244 shadow, 397, 472 sites for launching, 271 sound, 575-576 thunderstorm, 545-548 ray varying with air density, 243-244, 575-576, 861 weather map symbols, 275-276 curved, in air, 575-576, 861 refractivity, radar, 243-244 rainbow(s), 837-841 equations for air, ice, and water optics, 833-868 refractometer, microwave, 111 5th order, 840 geometry, 833-837 regression, linear, 770 Alexander’s dark band, 841 critical angle, 837 relationships and graphs, 873 colors, 839-840 for halos (ice crystals), 842-855 linear, 873 luminous meteors, 205 for rainbows (liquid water drops), 837-841 logarithmic, 873-874 moon bows, 841 Huygens’ Principle, 837, 859 power, 874 optics, 837-841 reflection, 833-837 relative orientation, 837 refraction, 833-837 circulation, 366 primary, 839-840 Snell’s law, 834-837 frequency of wind speeds, 645-646 quaternary, 840 light, 833-868 helicity, 588-591 red bows, 841 path, 833-861 humidity, 92 reflection, 841 equation for sound refraction, 575-576 definition, 92 renaissance, 841 equation for light refraction, 861 equation, 92 sea-spray, 841 sound, 575-576 in clouds, 189 secondary, 840-841 Rayleigh scattering measurement of, 76-79, 111 supernumerary, 838, 860-861 haze, 856-858 reduction of, in WBF, 201-202 tertiary, 840 of microwaves from radar, 245 saturation, 92 thunderstorm conditions for, 545-546 of light, 857 supersaturation, 186 twinned, 841 blue sky and red sunsets, 857 thermo diagram, 133-134 raindrop (see also drop, or precipitation) Rayleigh, Lord, 863 maxima and minima, 138-139 drizzle, 546 read, how to operating characteristic (ROC) curve, 783-784 growth processes, 205-207 METARs and SPECIs weather reports, 270-279 vorticity, 320-321, 362-363 optics, 837-841, 856-861 weather maps, 274-279 geostrophic, 319 shapes, 255, 545-546 rear-flank downdraft (RFD), 482-483, 492-495 sign convention, 320, 362 terminal fall speeds, 203 rear inflow jet (RIJ), 488-491 south /north side changes, 446 typical sizes, 185, 545-546, 857-861 derecho, 494 tornadic, 586-591 from stratiform clouds, 546 reasoning, inductive and deductive, 107-109 typical order of magnitude, 362 from thunderstorms, 545 recency symbols on weather maps, 276 variation with distance in planetary wave, rainfall , 99 receptor, pollutant, 724 368 accumulations, storm total, 257 record rainfall rates, 208, 545-548, 637 winds, 584 categories, 247 rectangular (Cartesian) coordinate system, 2 reliable, 782 coverage, 545-546 recursive techniques, 103, 771 reliability, 782-783 distribution worldwide, 209 red diagram, 782-783 intensity, 207-208, 247 bows, 841 relative, 783 levels, 247 color defined (also see optics chapter), 37, 834 remote sensors, 134, 219-266 likelihood, 782-784 Deer, Alberta, 553 on ground, 240-260 radar observations, 245-257 giant star, 803 radar (see radar), 240-260 rate, 72, 108, 207-208, 545-548 glow sunsets, 805, 858 satellites (see satellites), 219-239 and cyclogenesis, 465-467 sky, 858 renaissance and rainbows, 841 and latent heating, 72, 465 sprite, 563, 568 Rene Descartes, 2, 841 definition, 208 sun, 858 repeatable errors, 875 IDF (intensity, duration, frequency), 208 sunsets, 857-858 replacement cycle for hurricane eyewalls, 605 polarimetric radar estimates of, 257 reduced gravity, 135-136, 316, 658 reporting observations, 875 radar Z-R estimates of, 247 in Bernoulli’s equation, 670 reports, weather, 267-273 records, 208, 545-548 reduction of storm damage, 532 storm-total accumulations, 257 data (also see statistical methods), 823 research aircraft, 135 thunderstorm, 482 method to sea-level pressure, 267 reservoirs of momentum, 375 raining cats and dogs, frogs, fish, nuts, animals, etc., reference residence times of air in airmasses, 392-397 206 height for surface wind measurement, 701 residual layer (RL), 692-696 rain-free cloud base, 483 state, 316 drylines, relationship to, 416-417 random Earth climate/radiative equilibrium, 794, temperature, 416-417 errors and precision, 777, 875-877 807-808 residuals, finding unknowns as, 340 number generator, 184 feedback-processes, 806-807 resistant statistics, 502 range vapor pressure, 88, 880 resistance, electrical, 564 factor in the radar equation, 245-246 reflected pollutants, 734 resistivity, 565 -height indicator (RHI), 242 reflecting telescope, 293, 862 resolution mountain, 397 reflection coarse, 752, 815 radar, 240-241 definition, 833 fine, 752 ranked data, 502 from ice crystals, 842-844 frequency-distribution, 646 Rankine combined vortex (RCV) for tornadoes, 577- from water, 838-839 numerical weather prediction, 750, 752, 761, 816 578, 599 of radiation, 41, 219, 833-844 subgrid scale (unresolved), 750, 816 RAOBs= Radiosonde Observations (see rawinsonde), rainbows, 841 vs. grid spacing, 761, 816 272 reflectivity, 41-42 resolving the geostrophic paradox, 459, 462 rapid albedo, 42, 793-794 resonating air in lee wave, 667 changes in weather due to short waves, 370 differential, 256 response, feedback, 806-810 cyclogenesis, 426 equation for radar, 245-246 ice-albedo, 808-810 baroclinicity, 426 factor for radar, Z, 245-248 negative (damped), 807 conditions needed, 426 for water, 838 no-feedback, 807, 809 static stability, 426 radar (the name for scattered energy), 240-241 positive (amplified), 807-809 912 INDEX R, S

runaway, 807 momentum transport, 375-376 polar orbiting (POES), 228-229 restoring force, 136-137, 367-374 size (wavelength; wavenumber), 367, 369 radiative transfer, concepts for, 220-226 retired hurricane names, 615 stationary (lee side), 443-444 remote sensing from, 219 retrieval of soundings by satellite, 235-239 Rossby, Carl-Gustav, 399, 749, 759 retrievals, 235-239 corollaries 1, 2, 3, 235, 236, 239 rotating difficulties, 239 return planet; boundary layer growth on, 689 sensors, 273 flow storms (also see vortices) sounder, 235-239 antimountain, 653 cyclones, extratropical lows, 425-480 sounding pre-thunderstorm, 496 antivalley, 654 hurricanes, typhoons, tropical cyclones, 603- triangulation, 291 sea-breeze, 654-655 644 types, 227-229 periods of disasters vs. intensity, 208, 547, 646 mesocyclones (thunderstorms), 492-495, 587- SATEM code, 269, 273 stroke(s) of lightning, 567, 569 592 SATOB code, 269, 272-273 returned energy from radar, 245-246 tornadoes, 577-592 SATRAD observation locations, 273 returning airmass code, 392 rotation saturated (see also moist) returns from radar, 240 angular momentum, 360-361, 617 adiabat on thermo diagrams, 119-158 reverse flow in cavity, 667 forces, 296-299 adiabatic lapse rate, 101-106 reversible process, 121 hurricane, 617-619, 626-629 plot using spreadsheet, 103 revolutions, scientific, 773 lines in spectra, 221 for determining static stability, 139-141 Reynolds stress, 701, 712-713 rate of Earth, 297, 879 air, 87-98 vs. turbulent momentum flux, 712-713 changes of, 376 air parcels, 130 Reynolds, Osborne, 701 solid body, 363, 577 absolutely unstable, 140 RFD (rear-flank downdraft), 482-483 supercell thunderstorms, 483, 586-587 neutral stability, 140 RHI radar scan, 242 tornadic origin of, 586-587 saturation (see also equilibrium), 87-90 ribbon lightning, 568 wind-vector, in sea breeze, 656-657 absolute humidity, 91 Richardson number rotational invariance, 320 humidity, 87-96 bulk, 141, 710 rotation-angle of Earth, 229, 268-299 vs. air temperature, 88, 92, 100 dynamic stability, 141-142 rotor circulations, 165, 667 in clouds, 159-161 shear, 522, 530-531 rotor clouds, 165, 667 level (also see Lifting Condensation Level), 93- thunderstorm, 521, 530-531 roughness length, 677, 700-702 94, 130 critical, 142, 880 Davenport-Wieringa classification, 700 mixing ratio, 91-92 flux, 709-710 round-off error, 759 processes causing, 159-161 gradient, 710 rule(s) for cooling, 159 Richardson, Lewis Fry, 708, 759, 762, 764 determining static stability, 138, 688-689 moisture addition, 160 ridges (see also midlatitude), 332 determining unstable regions, 138 mixing, 160-161 axis symbols on weather maps, 281, 367, 391, 399 drawing isopleths on weather maps, 280-281 relative humidity, 92 formation and characteristics, 367-376, 391 runaway feedback, 807 specific humidity, 91 highs, relationship to, 390 Runge-Kutta method, 757 vapor pressure, 87-90 in Easterly waves, 611-612 running average, 599 ice vs. water, 88, 201-202 in Rossby waves, 353, 367-376 runway savings time, daylight, 5, 6 right direction, 646-647 sawtooth shape of Rossby waves, 374-376 hand rule for ageostrophic wind direction, 455 visual range (RVR), 270 Sawyer-Eliassen circulation, 412, 415 moving supercells, 518-520 change criterion for SPECI, 270 SB-CAPE, 503-505 quadrant of in METAR, 270 sc (stratocumulus clouds), 168 hurricane, 627 scalar equation, 293 jet streak, 454-456 scale RIJ (rear inflow jet), 488-491 analysis, 623 riming of ice crystals, 199, 202, 546 height rings of light in the sky (see optics), 833-868 S for density, 10 rising S band radar, 242 for pressure, 8 air parcels, 129 S time zone (Central & Mexico), defined, 5 length motion in cyclones (lows), 356 safe room (above-ground tornado shelter), 529 buoyancy, 733 pressure in cyclones, 463 safety dissipation, 709 symbol on weather map, 278 hurricane, 638-639 momentum, 733 risk of severe weather (convective outlook), 528-530 index, livestock weather, 117 velocity lightning, 567-571 buoyancy, 68-69, 109, 703-704 roads, as threat during storm chasing, 517 when storm chasing, 485, 517, 567, 570, 583-584 mechanical turbulence, 701-703 mirages on, 862 Saffir, Herbert, 607 scales of motion, 315 robust statistics, 502 Saffir-Simpson hurricane wind scale, 605-607 vs. forecast skill, 768 ROC curve and diagram, 783-785 Sagan, Carl, 415, 869 scan strategies and angles for radar, 241-242 skill score, 784-785 sails on frigate, 635 scattered rocketsonde, 134 salt, 188, 190-192 cloud cover, 170, 279 Rocky Mountains, chinook winds, 676-677 saltation, 562 light, 33, 219-222, 856-858 ROCOB code, 269 sample volume, radar, 240 rain showers, 545-546 SHIP, 269 sand, 170 scattering, 856-858 ROFOR code, 269 lithometeors, 205 backward, forward, 219, 857-858 roll saltation, 562 blue sky, 857 cloud (undular bore; wave, volutus cloud), 169 storm (haboob), 562 by aerosols, 221, 805, 857-858 vortices, horizontal, 167 weather-map symbols for, 275-276 from volcanic SO2 in stratosphere, 805, 858 root-mean-square (RMS) error, 778-779 San Francisco (advection) fog, 173-175 by air molecules, 220-222, 857 of 50 kPa geopotential heights, 778 Santa Maria volcano eruption, 805 directional variation (forward vs. backward), rope shaped tornado, 577, 583 SAR (synthetic aperture radar), 230 219, 857 rosette shaped ice crystals, 199 SARAD code, 269 geometric, 857 Rossby SAREP code, 269 Mie, 858 deformation radius, 344 satellites, 219-239 of energy from radar, 240-241 and geostrophic adjustment, 344 16 satellite, 222-235 of radiation, 219-222, 856-858 external radius of deformation, 405-406, 665 ABI (advanced baseline imager), 222-235 of visible light, 856-858 internal radius of deformation, 319-320, 344, channels, 222-223, 230-233 optical depth/thickness, 805, 856 665 geostationary (GOES), 227 polarization, 856 use in baroclinic waves, 372-373 humidity observation from, 112 Rayleigh, 857 ise in coastal jets, 664-665 hurricane tracking, 637 transmitted light, 856 number, 306 image interpretation, 231-235 twilight, 857-858 curvature, 306 imager, 230-235 types, 856-858 defined, 306, 313 locations of weather observations from, 272-273 visibility, 856-858 frontogenesis issues, 411 vs. wavelength, 857-858 vs. geostrophy, 306 loop (of images), 227 white clouds, 857 wave(s) (also called planetary waves), 332, 353, low-light-level cameras, 569 scatterometer sensors on satellites, 230 367-376 Meteosat images, 228 locations of observations, 272 characteristics, 373-374 observed Total Solar Irradiance, 39 schedule, forecast, 762 definition, 367 observations of hurricanes, 603-605, 608, 614, 616, Scheiner, Christopher, 855 forecasts, 370 620 Scheiner’s 28° halo, 855 heat transport, 339, 374-375, 378 optical transient detectors, 569 Schwarzchild’s equation for radiative transfer, 224- highs associated with, 391 orbits, 227-229 225 instability, 367-376 photos of Earth, 228, 232-233 Science Graffito and Graffiti, scattered in most chap- S R. STULL • PRACTICAL METEOROLOGY 913

ters sensible heat (enthalpy), 58, 671 1-D normal, 572 anonymous, 16, 31 flux at the surface, 73-76 wave, 571-574 science sensitive dependence to initial conditions, 773-776 short atmospheric, 205, 877 sensitivity, 350, 810 gap winds, 661-662 fundamentals, 869-878 climate, 810, 812 range weather forecast models, 768 high-risk, high-gain, 863 definition, 350, 810 scale number prefixes (for USA), 870 on doing, 877 factor, 812 waves (see also planetary waves), 369-370, 372 philosophies, 877 magnitudes, 812 short-wave scientific studies, 350 radiation (see also radiation, solar), 37, 220, 793 basis for numerical weather forecasts, 746-751 sensors (see weather instruments) Rossby, 369-370 laws (see Laws) in situ (direct) transmitted, 805 method, 2, 26, 343, 680 definition, 219 shoulder region of window, 220-223 mistakes & pitfalls, 863, 877 list of, 219 Showalter stability index (SSI), 531 notation for numbers or values, 870 remote, 219-266 showers, symbols on weather maps, 275-276 paradigm shifts, 863 definition, 219 SI (Système Internationale) - international system of paradox, 293 radar, 240-260 units, 8, 870 philosophies, 167, 293, 680, 877 satellites, 220-239 Siberian problem solving methods, 72 separation of variables, 89 high, 354-356 revolutions, 26, 773, 863 sequestered carbon dioxide (CO2), 812 traps, 805 thought, expert vs. novice, 72 set of data, reporting, 875 sidereal (relative to the stars) tools, 877 setting sun, shape of, 862 day, 227, 297 scientists, 877 severe Earth year period, 29 mistakes made by great scientists, 863 hail, 548 moon orbital period, 27 passion, 877 thunderstorm sigma (s) responsibilities as a citizen, 738 definition, 528 coordinates, 746 young, 293 environment, 496 model, 746 score, forecast skill, 777-785 intensity forecasting, 501, 507, 516, 521-522, plume spread standard deviation, 729 scorpion analogy (sting jet), 414-415 524, 530-531 velocity standard deviation, 727 scour of beaches by ocean waves, 634-635 probabilistic forecasts, 529 sign screen, Stevenson, 115 watches and warnings, 528-530 coefficient (centrifugal force), 296 scrolls on ice crystal plates, 199 weather positive or negative, in scientific notation, 870 sct (scattered) cloud cover, 170 forecasting & risks, 528-530 signals, 219-220 scud (cumulus fractus), 483 Storm Prediction Center (SPC), 532 signal strength from radar, 245-246 weather-map symbol for, 277 SWEAT index, 531 signature sea breeze, 654-657 SFAZI code, 269 damage to crops and forests, 593 front, 655-656 SFAZU code, 269 horizontal divergence (downburst outflow), 253, radar observations of, 249 sferics, 568 561 thunderstorms triggered by, 525, 654-655 SFLOC code, 269 tornado vortex (TVS), 253 head, 655 shadows significant high-pressure associated with, 391, 654-655 aircraft, glory optical phenomena around, 860 hail, 548 sea-level radar, 241 parameter (SHIP), 530-531, 551-552 density, 10 rain, 397, 472 levels, 134-135, 147 pressure shaft tornadoes, 501, 507, 516, 522, 530-531, 580 change, as plotted on weather maps, 277-278 hail-, 553 parameter (STP), 530-531, 592 cyclone-intensity measure, 426, 463-467 work, 672 silicon window on IR radiometers, 45 in various units, 7 shallow, weather-map symbol for, 276 silver iodide, 195-196, 553-554 mean, 267 shallow water wave speed, 633 similarity theory, 699-704 METAR, 270 shapes of simple is best (Occam’s razor), 680 on weather maps, 275, 434 clouds, 171 simplified (toy) models, 330 reduction methods, 267 tornadoes, 577 of global circulation, 330-334 tendency, 277-278, 463-467 Shapiro-Keyser cyclone model, 414-415 of hurricanes, 626-629 rise due to hurricane, 632-634 shear (also see wind shear), 509-522 Simpson, Robert, 607 temperature (average), 7 bulk Richardson number, 522, 530-531 sine law of radiation, 40 sea-spray rainbow, 841 components, 509 singing wires (aeolian tones), 560 sea surface temperature (SST), 608-609, 616 direction, 509 single-cell thunderstorms, 486 climate variations, 818 frontal, 407-412 single-layer shear, 514 role of cold temperatures in hurricane death, frontogenesis, 407-412 sink, level of free (LFS), 557 616 generation of TKE, 708-710, 727 sinking, 135 warm anomaly, 818 geostrophic wind, caused by thermal wind, 345- sirens, civil-defense, 529 ENSO, 818-820 349 sizes of PDO, 818-820 hodograph usage to determine, 509-522 clouds, 170 sea water density, 880 isoshear, 18 hydrometeors, 187 season(s) line, 281, 399 skc (sky clear), 170 Earth, 30, 797-802, 879 local (single layer), 514 skeletal shaped ice crystals, 199 hurricane, 630 magnitude, 509, 515-516 skew-T log -P diagram, 121-158 seasonal mean vector, 514 components, 124 averages (months used for), 330, 333 production of turbulence, 704, 710 creation of , 124-125 differences in atmospheric boundary layer, 695- single-layer, 514 skewness factor, 125 696 speed, 509-510 ski runs, 209 forecast models, 768 surrogate using wind difference, 509 skill heating cycle, 30-33, 40-41, 332-333, 354-358 total magnitude, 515-516 climatology, 780 seasonality of hurricanes, 630 turbulence production, 704, 710 forecast (NWP), 752, 777-785 second, 870 units, 509 persistence, 780 secondary vorticity, 362 scores, 777-785 circulation (Sawyer-Eliassen) at fronts, 412 wind, 706 vs. forecast time, 775, 780 associated with jet streaks, 455-456 radar observations of, 254 vs. scale of event, 768 fields, 772 hurricane environment, 610 vs. spread of ensemble forecasts, 777 rainbow, 838, 840-841 thunderstorm environment, 496, 509-522 skin of air parcel, 57 variables in NWP, 771-772 shearing deformation, 320-321 sky wavelets, 859 sheath ice crystals, 198-199 color, 857-858 sector plate ice crystals, 198-199 sheet lightning, 567 cover, 170 seeding of clouds, 195-196, 218, 553-554 sheets of clouds, 168 weather-map symbols for, 279 cavum (hole in cloud layer from seeding), 169 shelf clouds, 562 transmissivity, net, 44 self development of cyclones, 468-471 shield of stratiform clouds, 425-428 slab model, 697-698 semi- from hurricanes, 604 slalom ski snow, 209 Lagrangian method of NWP, 761 from thunderstorm MCS, 488 slanting data, 826 log graph, 873-874 shifting winds, 349, 400-401 sleet (ice pellets), 199, 276 major axis of Earth’s orbit, 28, 800-802 shimmering mirages, 862 slight thunderstorm risk, 530 precession, 800 SHIP sling psychrometer, 94 minor axis of Earth’s orbit, 28 code, 269, 271 slope transparent (=translucent), 42, 169, 220 parameter, 530-531 definition, 396 Seneca, 523 shock on log-log graph, 215 sense (direction) of circulation, 456, 377-378 front, from lightning, 571-574 flows (anabatic, katabatic), 649-653 914 INDEX S

force of katabatic winds, 396, 651-653 upwelling radiation, 44-47, 220-226, 230-239, 797 special crystal orientations, 855 of storm surge, 633 variability, 39 species of clouds, 168 statistical calculation, 770 wind, 376 SPECI code (special meteor. aviation report), 269-271, SLP, sea-level pressure, units, 7 zenith angle, 33 275-279 small Solberg, H., 399 criteria that trigger issuance of, 270 disturbance errors, 875 solenoid specific nuclei, 188 on weather maps, giving max advection, 458 differential phase, 256 smog (see also pollution), 193 term, in the circulation equation, 366 heat brown cloud, 857-858 solid air, 53, 55-56, 58, 880 smoke, 170 angle, dimension and units, 870 at constant pressure, Cp, 53-56, 880 concentration distribution, 734, 737 body rotation at constant volume, Cv, 55, 880 dispersion, 710, 723-744 in tornado core, 577-578 of humid air, 56 lithometeors, 205 quasi-geostrophic vorticity, 449 of liquid water, 54, 56, 880 plumes, 710, 724 relative vorticity, 363 of water vapor, 880 edge, 730 solitary wave (bore; roll cloud), 169, 656 ratio, 880 footprint, 733 solstice, summer and winter, 30-31, 801, 879 humidity, 91 stack, 723-724 solute, 190-192 saturation value of, 91 clouds, 166 solute effect, 189-193 volume, 11, 121 weather-map symbol for, 276 solution to pollution, 724 isostere, 18 smoothing data, 826 solutions work, 121 smoothness, Lipschitz, 761 in water droplets, 190 spectral snapshot of smoke plume, 728 to atmospheric equations, 749 absorption, 222-223 Snell, Willebrod van Royen, 841 solving problems, 72, 869 hygrometer, 111 Snell’s Law sonde (instrument to make soundings), 134 lines, 221 for light, 834-837 dropsonde, 134 dispersion, 834 3-D, 836 radiosonde, 134 radiance constants, 221, 879 for sound, 575 rawinsonde, 134 transmittance, 222-223 Snelling, 765 rocketsonde, 134 spectrometer, 46-47 snow weather balloon, 134 spectrum accumulation and liq. water equivalent, 107, 208- sonic electromagnetic, 220-223 209 anemometer, 321 light (colors), 37, 222, 834-835, 862 banner cloud, 165 thermometer, 78 width, 254 capped mountains, viewed from satellite, 234 soot, 151 speed (see also velocity) characteristics, 209 sound airspeed, indicated with pitot-static system, 674 condensation onto, 110 howling in storms (aeolian tones), 560 constant (isotach), 18 dendrites, 198-199 rays in air, 575-576 equation, 2-3, 314-315, 746 density, 209 refraction of, 575-576 difference in jet stream, 450-453 depth sensor, 210 speed/velocity, 572, 575-576, 674, 880 group, 658 eater, 676 supersonic thunder shock wave, 571-574 of dry line movement, 417 formation in cold clouds, 201-202 waves, 571, 575-576 of electromagnetic radiation, 243 grain classification, 199, 209 transition from shock waves, 571 of light, 36, 240, 243, 834-837, 879 weather-map symbols for, 276 sounder of rain drops (see terminal velocity), 202-204 melting into rain, 206 channels on satellites, 222-223, 226, 235 of sea-breeze front, 655-656 optics (ice-crystal optics), 163, 842-855 operation on satellites, 235-239 of sound, 572, 575-576, 674, 880 pellets (graupel), 199, 546 soundings, 119 of wind, 2, 3, 302-314 weather-map symbols for, 276 environmental, 59, 134 around highs and lows, 307 pillow, 210 locations worldwide, 271 Beaufort scale, 635-636 powder, 209 mandatory levels, 134, 772 in hurricanes, 605-607, 626-629 shapes, 198-199 methods, 134-135, 496 in tornadoes, 577-580 strength, 209 pre-thunderstorm, 496-499, 503-508 total (rotation + translation), 578, 627-628 swath on the ground, 163 retrieval by satellite, 235-239 phase, 369-370, 658 symbols on weather maps, 208, 275-279 significant levels, 134, 147 shear (shear magnitude), 509-510 thunder-, 207 to determine boundary layer depth, 143 updraft, 649 snowball Earth, 811 to determine CAPE, 503-508 wave, 658 snowfall rates, 208-209 to determine clouds, 162-164 spheres, layers in atmosphere (e.g., troposphere), 12- snowflakes as aggregates of many crystals, 200 to determine tropopause height, 143, 496 13, 563 SO (Southern Oscillation), 818-819, 824 source electrosphere and ionosphere, 565 social aspects of hurricane hazards , 631 height of pollutant emissions, 723 spherical sodar, 219 latitudes for angular momentum, 361, 375 coordinates, 747 sodium chloride (salt), 190-192 location for parcels, 360-361, 711 cow, 330 SOI (Southern Oscillation Index), 818-819, 824 of pollution, 724 spider lightning, 567 solar of turbulence, 69-71, 138-142, 666-668, 705-715 spin (see vorticity), 320-321 activity variations, 803 of weather data, 271-273 spin down azimuth angle, 33 point, 724 of cyclone, 429 blackbody radiation emitted, 37, 39 receptor framework, 724 of Earth, 376 cells (photovoltaics), 46 south direction (opposite north), 2 of global circulation, 388 constant (total solar irradiance), 39-45, 793-794, South spin-up 879 Atlantic subtropical high, 354 rate of cyclones, 446-451, 617 kinematic, 879 Pacific subtropical high, 354 of global circulation, 388 variations, 803 Pole, 4 of hurricanes, 617 declination angle, 30-31, 802 Southern of tornadoes, 586-587 downwelling radiation, 793 annular mode (SAM), 824 of vorticity, 446-451, 586-587 elevation angle, 32 Hemisphere, 4 spinning forces, 296-299 vs. latitude, 40, 334 defined, 4 spiral emission of radiation, 37-39 continential low, 354 bands in tropical depressions & hurricanes, 604- faculae, 803 global circulation, 332, 339, 343, 350-358 605, 613-615 forcing ratio, 813-815 midlatitude cyclones (lows), 426, 430-432 Ekman (in ocean), 378 heating and cloud formation, 162 semi-permanent monsoon names, 354 pattern (waterspout evolution), 582 incoming radiation, 39, 334-337, 793, 797, 801-802 sign of Coriolis force, 297, 301 spissatus/spi, 168 input, net, 795 sign of centrifugal force, 296 Spörer minimum in solar activity, 803 insolation, 40, 336, 793, 797, 801-802 Indian Ocean High, 354 spotters, storm, 529 irradiance, 37-39, 793-794, 879 oscillation index (SOI), 818-819, 824 spray, 170, 276 luminosity parameter, 813-815 SO2, sulfur dioxide, 7, 725, 804, 858 ring (waterspout evolution), 582 net input to Earth, 795 space spread output variations, 803 dust, 376 parameter, Weibull distribution, 646 radiation, 37-39, 220 outer, satellite images of, 234 interquartile range (IQR), 502 astronomical influences, 797-803 Space Science and Engineering Center (SSEC), 232 smoke plume, 729-730 driving the global circulation, 329, 334-339 spatial temperature-dew-point, 92 transmitted, 805 distribution of pressure /temperature, 280, 343, vs. skill, 777 radiative forcing, 40 359 spreadsheet radius, 33 gradients; finite-difference approximations, 754- programs and samples, 20-21 tides, 376 755 thermodynamics, 63, 103 total solar irradiance (TSI), 39, 793-794, 803, 879 SPCLI code, 269 thermo diagrams, 63, 100, 103, 125 S R. STULL • PRACTICAL METEOROLOGY 915 springs (illustrating Brunt-Vaisala oscillation), 136 scientific notation, 870 empirical orthogonal function (EOF) analysis, Spring (vernal) equinox, 30-31, 801 STP, 7, 107, 880 820-823 sprite, red, 563, 568 temperature, 7, 107, 880 error, 778, 875-877 squall, weather-map symbol for, 276 time, 5 propagation, 876-877 squall line of thunderstorms, 488, 490-491 uncertainty, 875 forecasts, 816 predicting, by using total shear magnitude, 516 standardized wave shape for lightning surge, 569- Gaussian distribution, 184, 729-730, 875 570 intercept, 770 radar image of, 243 standards, air-quality, 725 interquartile range (IQR), 502 tornadoes () from, 582 standing lenticular clouds, 165, 666-668, 684-685 Kalman filtering & gain, 770 weather-map symbols for, 281 optical phenomena caused by, 859-860 least squared error, 770 SR (storm relative), 584 start shaped ice crystals, 199 linear regression, 770 SRH (storm relative helicity), 530-531, 588-592 star(s) matrix, 822 SSM/I (Special Sensor Microwave Imager), 230, 273 red giant, 803 mean (average), 502, 726, 875 visible at night, 33 absolute error (MAE), 778 SST (sea surface temperature), 608-610, 616 white dwarf, 803 error (ME), 778, 875 st (stratus clouds), 168 state squared error (MSE), 778 stability, 119-158 equation of, defined, 14-15 squared error skill score (MSESS), 778 absolute, 140 of air, 2 median, 502 airmass, 391-396 of parcel, 128 method of moments, 730 cloud type vs., 161-164 thermodynamic, defined, 2, 6 model output statistics, 770-771 conditionally unstable, 140 on a thermo diagram, 100, 128 updateable, 771 cyclogenesis, impact of stability on, 426 USA, in, 431 normal distribution, 729-730 dry absolutely unstable, 140 static outliers, 502 dry neutral, 140 AM radio, 568 percentiles, quartiles, 502 dynamic, 141-142 definition, 16 predictands and predictors, 770 flow, 138-142 electricity, 564 perfect prog method (PPM), 770-771 in stratosphere, 143-144 hydrostatic, 15-16, 340, 651, 747 principal component analysis (PCA) methods, in troposphere, 143-144, 688-690 instabilities and circulations, 132 820-823 indices for thunderstorm & tornado forecasting, formation, 162 probabilistic forecasts, 777 530-531 -pitot system for air speed, 674 propagation of errors, 876-877 neutral, 138-140 pressure, 7, 672-674 random number generator, 184 nonlocally unstable, 138-139 stability, 138-141, 687-689 rank, 502 numerical, 759-761 airmass, 391-396 recursive, 771 Paquill-Gifford classification, 727-728 air parcel method, 138-139, 687-688 regression, 770 rules for determining, 138-141 apex method for determining, 138-139 root mean square error (RMSE), 778 saturated absolutely unstable, 140 atmospheric boundary layer, 687-689 running average, 599 saturated neutral, 140 cloud formation within, 162-163 slope, 770 smoke dispersion, vs., 732-737 estimation, 728-729 standard static, 138-141 forced vs. free convection, 710 deviation, 502, 706-708, 727, 875-877 turbulence determination, 142 frontal, 414 uncertainty, 875 unstable, 138 layer method for determining, 140-141 thunderstorm & tornado likelihood, 501-502, 507, stable misinterpretation, 729 516, 522, 538, 588-592 absolutely, 140 neutral, 139-140, 688-689, 710 trace of matrix, 822 air, 138-142 nonlocal, 138-139 variance, 706-708, 727, 821 boundary layer (SBL), 692, 696 parcel method for determining, 138-139 verification of weather forecasts, 777-785 cold airmass genesis, 393 rules for determining, 138-139, 688-689 statistical theory (Taylor’s) for pollutant dispersion, depth, 696 smoke dispersion in, 710, 723-744 731-732 e-folding height, 696 stable, 136-137, 139-140, 688-689, 710 statistics smoke plume rise within, 733 thunderstorm, 496-499, 503-508 dispersion, pollutant, 728-730 strength, 696 unstable, 138-139, 688-689, 710 non-parametric, 502 temperature, 692-696 temperature, 672-674 resistant & robust, 502 turbulence, 707-710 statically stable air, 136-140 turbulence, 706-708, 726-728 velocity standard deviations, 707 clouds that form in, 163, 165 verification of forecasts, 777-785 Brunt-Väisälä frequency, 136-137 mirages in, 861-863 vs. life, 726 definition, in flow stability, 138 statically unstable air, 128-142 Steadman, R.G. Heat Index, 77, 117 equilibrium of droplets, 191 clouds that form in, 161-162, 164 steady pressure symbol on weather map, 278 regions, 138-140 mirages in, 861-863 steady state surface-layer wind, 702-703 smoke plume dispersion in, 735-737 atmosphere (radiative equilibrium), 795 stably-stratified station definition, 302 flow, 657-661, 688-689 ID or weather station code (ICAO), 270 flow, 669 turbulence related to PG types, 710 Papa, 288 radiation balance of Earth system, 794 staccato lightning, 568 plot model on weather maps, WMO, 274-279 winds, 302-314 stack height, smoke emission, 723 stationary in ABL, 699 stacking of pressure characteristics environment, 688 steam hurricane, warm core, 622 flow, 669 engines, 89 low-pressure, role in cyclolysis, 432-433 turbulence, 708 fog, 173 stages of evolution of front(s), quasi-stationary, 404 steering winds thunderstorm cells, 485 weather-map symbols for, 281, 399 hurricanes, 607-608 tornadoes, 583 mountain waves & lenticular clouds, 666-668 thunderstorm (normal storm motion), 487, 516- staggered arrangement of grid points, 753 planetary waves (& lee cyclogenesis), 443-444 518 Arakawa grids, 753 north-south amplitude & wavelength, 444 Stefan-Boltzmann stagnation quasi- , 281, 399 constant, 37, 337, 879 events for air pollution, 741 statistical methods law, 37-39, 337, 794 point, 672 adaptive, 771 stellar shaped ice crystals, 199 pressure, 673 average (mean), 502, 705, 726, 875 stencil, 757-758 streamline, 672-675 running, 599 stepped leader, 566 standard bell curve, 729-730 steps for problem solving, 869 atmosphere, 11-13, 688-690 biases (mean, systematic errors), 770, 778 steradian, unit of solid angle, 221-224, 870 definition, 11-13 binary event verification, 780-782 stereographic map projections, 748 density, 10-13 box-and-whisker diagram, 538 Stevenson screen, 115 in thermo diagram, 135, 688-690 calibrated ensemble forecasts, 777 Stewart, George R., 775 lapse rate, 11-13, 70, 688-690 categorical event verification, 780-782 sting jet, 414-415 static stability, 688-690 central-limit theorem, 184 Stokes Drag Law, 202-203 temperature, 11-13, 688 correlation coefficient, 711, 779 Stokes, George, 759 deviation, 706-707, 727, 875-877 anomaly, 779-780 Stone, Alex, 315 of pollutant location, 729-730 cost function, 766-767 storm (also see thunderstorms, cyclones or hurri- of wind components, 706-708, 727 covariance, 711, 821-822 canes) propagation in equations, 876-877 matrix, 822 case-study of extratropical cyclone, 433-466 variation with height, 707 cumulative probability threshold, 777 cells, 485 isobaric surfaces (upper air), 772 data reduction, 502 chasing, 484, 532 pressure, 7, 107, 880 dice, 184 core punching, 583 levels (mandatory), 772 discriminator of thunderstorm intensity, 507 safety, 485, 517, 567, 570, 583-584 refraction of radar beam, 244-245 eigenvalues and eigenvectors, 822 convective (see Thunderstorms), 496-499 916 INDEX S

damage scales (tornado), 579-580 urban, 678-679 blue, 858 data for case-study cyclone, 434-435 strength of crimson, 858 downslope wind, 667, 675-677 fronts, 408-412 distance to earth, 30, 802, 879 dust, 562 stable boundary layer, 696 aphelion, average, and perihelion, 879 evolution, 484-485 stress, 700-702, 712-715 dog, 842, 850-851, 854-855 hazards, for thunderstorms, 545-602 dimension of, 870 sub, 842, 851, 854-855 hail, 548-554 kinematic, 701, 712-713 elevation angle, 32 helicity, 587-592 molecular, 701 emission of radiation, 37-39 hurricanes, 603-644 Reynolds, 701, 712-713 evolution: red-giant start; white dwarf star, 803 intensity forecasting (indices for), 530-531, 588- vs. momentum flux, 712-713 faculae (surrounding sunspots), 803 592 turbulent (Reynolds), 701 green flash, 862 lghtning, 563-571 units, 870 halos around, 842-855 motion/movement of thunderstorms, 483, 488, stretching optical phenomena around, 163 510 deformation, 320-321 output variations, 803 normal, 516-518 in typical weather patterns, 447-451 pillar, 842-843, 854-855 left- and right-moving, 518-520 self-development of cyclones, 468-471 radius angle as viewed from Earth, 33 winds relative to, 584-585 term in vertical vorticity eqn, 447-451, 586-587 red, 858 movement of hurricanes, 615 striations, cloud, 483 shape when rising or setting, 862 Prediction Center (SPC), 532, 580 strike, lightning, 566 subsun, 842, 844, 854-855 pre-storm environment, 496-499 strokes, lightning, 567-568 synchronous orbit, 227-229 radar identification and observations of, 248 structure of younger, 803 relative (SR), 584 atmosphere, 11-13 zenith angle, 33 effective helicity (eSRH), 590 boundary layer, 13, 692 sundial time, 34 helicity (SRH), 530-531, 588-592 hurricanes, 604 sunlight, 131-132 winds, 584-585 Stull, Roland - about the author, XIV sunrise reports, 532 Stüve diagrams, 121-158 apparent & geometric, 33-34, 861-862 rotation, origin of, 586-587 subadiabatic time, 33-34 sand (haboob), 562 lapse rate, 140 sunset sounds, 560 region, 144 apparent & geometric, 33-34, 861-862 spotters, 529 subanthelic arc, 855 blue color, 858 strength, indices for forecasting, 530-531 subcategories of clouds, 168-169 red color, 858 surge, 615, 632-634, 669 subcircumzenith arc, 855 time, 33-34 heights, 633 subcritical flow, 659 sunshine, constant (isohel), 18 supercell, 483, 492-495 subgeostrophic wind, 304, 455, 699-700 and cloud formation, 162 system, 426 subgrid scale, 750, 816 sunspot thunderstorms, 481-602 subhelic arc, 854-855 activity or cycle, 39, 803 total rainfall accumulations, 257 subhorizon halos, 855 faculae, 803 track subjective (hand) analysis of weather maps, 279-281 number, 803 hurricanes, 607-608, 615 superadiabatic lapse rate, 139-140 extratropical cyclones (Lows), 429-431 sublimation, latent heat of, 56 supercell thunderstorms and tornadoes, 483, 516-520, subparhelia (subsun dogs), 842, 851, 854-855 thunderstorm, 482-484, 492-495 584, 593 subparhelic circle, 855 classic (CL), 492-494, 549, 553 tropical, 614-615, 635-636 subpolar composite parameter (SCP), 530-531, 592 typhoons, 603-644 lows, 331 effective (eSCP), 591 weather-map symbols for, 276, 426, 614-615 zone, 330 high-precipitation (HP), 495 winds (Beaufort scale), 635-636 subranges of turbulence, 315, 708 hybrid, 492 downslope, 667, 675-677 subrefraction of radar beam, 244-245 indices for forecasting, 530-531, 588-592 stormy-weather heat flux, 70-71 subsidence intensity forecasting, 501, 507, 516, 521-522, STP, standard temperature & pressure, 7, 107, 880 air pollution episodes and exceedences, 691 524, 530-531 straight-line winds (also see derecho), 489, 491, 494, around clouds including thunderstorms, 161, likelihood, 516, 530-531 554, 560-563 545-546 low-precipitation (LP), 495 downburst generated, 554-563 at top of atmospheric bounary layer, 691 motion, 518-520 radar observations of, 253, 560-561 by Ekman or boundary layer pumping, 319-320 normal storm motion, 516-518 strange attractors , 773-776 in anticyclones (highs), 356, 390-396, 691 right- and left-moving, 518-520 stratified in Hadley cell, 351 rotation (as a mesocyclone), 586-592 air layers at night, 653 in hurricanes, 629 storm-relative wind statistics, 585 fogs, 176-177 in troposphere of high, 390 tornadoes, 577, 582, 588-592 system, 657-661 on weather maps, 433, 437, 448, 451, 471 supercontinents (Pangea, Gondwana, Laurasia), 804 stratiform/stratiformis (advective) clouds, 94, 162- estimated from convergence/diverg., 441, 164, 168 449, 452, 455-456, 461-462 supercooled liquid water, 88, 98, 186, 194-195, 201- clouds in thunderstorm MCS, 488 radar estimates of, 252-253 202 drizzle from, 546 trapping of air pollutants, 691 glaciation of, 554 formed at frontal boundaries, 160, 425-428 subsun , 842, 844, 854-855 lightning creating, role in, 564-566 radiative effects in, 132, 160 subsun dog, 842, 851, 854-855 supercritical flow, 659 shield at warm fronts, 425-426 subsurface heat and water parameterizations for supergeostrophic wind, 304, 311, 455, 699-700 stratocumulus, 161, 164 NWP, 751 supergradient wind, 643 stratopause, 12-13 subtropical, 330 superior stratosphere, 12-13, 143 deserts, 351 airmass code, 392 isentropic potential vorticity in, 415 highs (anticyclones), 331, 351, 391 mirages, 862-863 pressure gradient in, 359 Southern Hemisphere, 354 supernumerary bows, 838, 860-861 temperature reversal in, 359 jet, 233, 331-332, 350-351, 357-361 superposition of light rays, 845 tight packing of isentropes, 143, 414 angular momentum, 360-361 superrefraction of radar beam, 244-245 winds in, 359 latitude dependence on Earth rotation, 351 supersaturated, 88 stratospheric zone, 330 air, 88 aerosols, 804-805, 858 suction vortices, 593 supersaturation, 185-187 air, 414-415 sulfates, 188, 811, 858 activating nuclei, 195 clouds, 166 sulfur dioxide, SO2, 7, 725, 858 available, 187 ozone, 364 aerosols and emissions from volcanoes, 804-805, background, 197 destruction, 724 858 critical, 192 stratus, 162-163 stratospheric, 804-805, 858 droplet growth rate, 190-192 in satellite images, 234 sulfuric acid, 188, 190-192 fraction, 186, 196-197 streaklines, 668-669 sultriness, 77 gradient, 196-197 streaks summer, 330 percentage, 186, 196-197 hail, 552 atmospheric boundary layer, 695-696 reduction of, in WBF, 201-202 jet, 454 simmer index, 117 water availability to make droplets, 186-187 role in upward motion & cyclogenesis, 454- solstice, 30, 801-802, 879 supersonic 456 year without (1816), 805 flight, 88 streamer (lightning), 566 sun (also see solar) shock waves in thunder, 571-574 streamlines, 611-612, 668-675 apparent supertyphoon, 607 stagnation, 672-674 rise and setting times, 33, 861-862 supplementary cloud features, 168-169 streamwise vorticity, 518, 587-592 shape during rise and set, 862 suppression of hail, 553 streets azimuth angle, 33 supralateral arc, 854-855 clouds, 167 blackbody radiation emitted, 37, 39 surf, 635 S, T R. STULL • PRACTICAL METEOROLOGY 917 surface (also see near-surface) times for NWP forecasts, 758 equator to pole, 336 albedo feedback (snow & ice cover), 810-812 weather maps, 274-281, 444 horizontal; meridional, 335 based CAPE, 503-506 synopticians, 444 in troposphere, 335-336 budget of radiation, 44-45, 797 synoptics, the field of, 444 near the ground, 335-336 drag, 300-301, 319, 447-448, 625, 632-634, 700-701 synthesis heat index, 77-78, 117 emissivity, 42 PCA reconstruction of data, 823 humidex, 77-78, 117 energy budget, global, 797 questions at end of each chapter, explained, 25 humidity index, 77-78, 117 fluxes, 67-69 synthetic aperture radar (SAR), 230 hurricane model, 621-622, 629 front, 399-412 Syracuse, 150 ice-albedo feedback, 808-812 attributes, 399 systematic errors (biases), 770, 777, 875 instruments, 78-79 glyphs (lines) on weather maps, 399 correction for dynamic warming, 673 horizontal structure, 400-402 inversion, 139, 144, 687-691 vertical structure, 403-407 isotherm, isothermal, 18 heat budget, 73-76, 797 Kelvin, defined, 7 Bowen ratio, 74-76 T lapse rate, 59-60 daily variation of, 74 T time zone (Mountain), defined, 5 latitude variation of, 335 units, 74 T-phi thermo diagram (tephigram), 122 layers of atmosphere, 12 heat flux table-driven code formats (TDCF), 268 lightning, of, 563 airmass modification by, 397-398 TAF (terminal aerodrome forecast) code, 269 liquid-water potential, 104, 500 bulk transfer relationships, 397-398 tail max surface, for thunderstorms, 506, 523 calm days, 68 beaver, 483 measurement, 78-79 effective turbulent, 68 cloud (cauda), 169, 483 correction for dynamic warming, 673 measurement, 75 winds, aircraft, 563 meridional gradient, 335-336 isobaric, 290-291 tailored weather forecasts, 772 METAR, 270 latent heat flux, 108 Talmud, 523 mixed layer, 692-698 layer, 308, 692, 700 Tambora, Mt., 805 modification in airmasses, 397-399 depth, 308, 692 tangent arcs, 851-855 molecular velocity, 6 log wind profiles, 702-705 lower, 851-8532, 854-855 of planets in the solar system, 22 neutral, 702 upper, 842, 851-852-854-855 potential, 61-64, 500 stable, 702-703 tangential profile, 3 temperature profile, 692-694 component, 249, 304-312, 320-321, 362-364, 577- evolution of boundary layer, 694-696 turbulence, 705, 709 581, 626-627 hypothetical, 3 unstable, 703-705 velocity vs. geopotential height, 11-12 winds, 692, 700-705 hurricane model, 626-627 radiative moisture flux, 108-111 hurricane winds, 622-623 emission, effective, 794 observations, 270-271 of earth, 298-299, 360-361 equilibrium, 794-797 automatic (ASOS and AWOS), 271 tornado, 577-580 reversal in stratosphere, 359 parameterizations in NWP models, 750 winds near surface, 622-623 sea-level, 7 radiation budget, 44-45 winds varying with altitude, 618-623 sensible energy, 54 longwave (IR), 45 Tarantian age, 799 sensors, 78-79 net radiation, 45, 797 tax, 711 sounding locations from satellite, 273 solar, 44 Taylor, G.I., 731 stable boundary layer, 696 roughness, 677-678, 700-703 Taylor series, 754-755 standard, 7 sensible heat flux, 73-76, 797 finite differencing schemes, 754-755 STP, 7, 107, 880 skin temperature, 67-68 truncation order, 754-755 static, 672-674 solar radiation, 44 Taylor’s hypothesis, 731 stratospheric, 359 temperature Taylor’s statistical theory for pollutant dispersion, surface, 12, 794-797 gradients, 66-75, 872 731 tendency, 64, 72, 746 max, for thunderstorms, 506, 523 TCU (see towering cumulus, or cumulus congestus), thermo diagram, 119-158 tension of pure water, 189, 215, 880 161-162, 165-166, 168, 482-485, 582 threshold for ice nucleation, 195 weather maps, 435, 437-438, 466 tectonic influences on climate, 804-805 units, defined, 7, 870 waves (in open channel hydraulics), 658-661 teleconnections, 832 urban-rural difference, 679 winds, 701 telescope, reflecting, 293, 862 variation of saturation humidity, 88-90 wind-waves, 634-636 TEMP code, 269, 271 virtual, 14-15 surfaces of constant DROP, 269 constant, 880 height above ground (= 0 for surface maps), 437 MOBIL, 269 virtual potential, 61-62 height above mean sea level (= 0 at MSL), 436 SHIP, 269 vs. height, 11-12, 127-145 potential temperature, 437 temperature, 6-7, 54, 870 near surface, 335 potential vorticity, 437 absolute, 7 weather maps, 274-275, 438-440 pressure, 436 absolute virtual, 14-15 wet-bulb, 94-96, 500 thickness, 436 absolute zero, 7 wind chill, 76-77 surge(s) advection, 65-67 zonally averaged, 335-336 power, due to lightning, 569-570 in grid cells, 750, 754-761 temperature influence on albedo (modeled), 808 probabilities, 569 role in self development of cyclones, 468-469 temperature-dew-point spread, 92 storm, due to hurricanes, 632-634 airmass, 391-397 temperature-humidity index (THI), 77-78 surplus radiation, 338 apparent, 76-78 tempest, 607 surrogate vertical velocity, for mass budget, 463-464 brightness, 211, 221-224 tendency, 18 Celsius, Centegrade, defined, 7 height, 463 Sutcliffe development theorem (for cyclogenesis), change with height, 11-13, 129-144 in forecast verification, 778 456 city (urban heat island), 678-679 pressure, at MSL, 463-467 Sverdrup, H.U., 399 climate, radiative balance, 794-797 term, 747 swamp coolers, 116 constant (isotherm), 18 temperature, 746 swaths of hail or snow, 163, 548, 552 contrasts between land and water, 356 tephigrams (also see thermo diagrams), 121-158 sweat, 93 convective condensation , 526-527 tera (1012), 870 index (severe weather threat), 531 conversion formulae , 7 terminal velocity of, 202-204 swell, 635 correction for dynamic warming, 673-674 cloud droplets, 202 swirl ratio, 530-531, 592-593 definition, 6-7 hydrometeors, 202-204 switching axes of graphs, 3 dew-point, 92-93 rain drops, 203, 555 symbols and notation, 481 isodrosotherm, 18 causing downbursts, 555 for ice crystals, 199 distribution over hurricane depth, 621-625, 629 hailstones, 204, 549 for fronts, 399 dynamic, 672-674 terminology, process, 18 for weather maps, 168-170, 208, 274-279, 614-615 Earth effective radiative, 794, 879 terrain (also see mountains), 365, 397-398 SYNOP code, 269, 271 equivalent potential, 104-106 following coordinate system, 746, 753 MOBIL, 269 errors, 766 influence on cyclogenesis, 443-446 synoptic evolution, 72-73, 746 terrestrial radiation (or IR or longwave), 37-39, 223 definition, 268, 274 excess in cities, vs. population, 649 tertiary rainbow, 840 observations, 268-273 Fahrenheit, defined, 7 TESAC code, 269 meteorology, 353, 444 field, 280, 343, 359 Tetens’ formula, 90 scale, 315, 444 forecast equations, 746 Texas, USA, 416, 431, 560 cross-mountain pressure gradient, 661-664 frost-point, 92 theoretical divergence, 393-396 global warming, 796 meteorology, 872 vorticity needed for hurricanes, 610 gradient winds, 302-313 weather, 274, 444 derivation of equation, 336 thermal(s) 918 INDEX T

belt for crops on mountain slopes, 653 processes, 100-106, 121, 129-133 bow echo, 490-491 circulations, 341-342, 356, 648-657 dry (unsaturated) lifting/lowering, 129 bursticane, 602 in hurricanes, 613 moist (saturated) lifting/lowering, 130 CAPE, 503-508, 530-531, 590 in local winds (e.g., sea breezes), 655 precipitation, 130-131 cauda (tail cloud), 169 clouds, in, 162 radiative heating/cooling, 131-132 cells, 484-485 convective, 649, 694, 710 pseudoadiabatic assumption, 121 change criterion for SPECI, 270 diameters, 648-649 relative humidity, 133 chasing, 484 drag, felt by, 648-649 saturated adiabats, 102-106 safety, 485, 517, 567, 570, 583-584 energy transferred, 58, 672 saturated (cloudy or foggy) air, 128, 130 CIN (convective inhibition), 522-526, 590 internal boundary layer (TIBL), 654-657 saturation mixing ratio, 128 classic supercell, 492-494, 549, 553 lidar image of, 649 soundings, 134-135 cloud shield, 488 low, 341-342, 356, 430-431 spreadsheet construction of, 63, 103 clouds associated with, 482, 488, 494 rise, 649, 710 state, 100, 121 cold-pool of air, 488 scales of motion, 315 temperature, 128 conditional instability, 141, 498, 503-508 stress index, 117 thunderstorm thermodynamics, 496-526, 557- convective available potential energy (CAPE), updraft, 648-649 558 503-508, 530-531 upside-down, cold-air sinking, 177, 396 total water mixing ratio, 128 convective conditions, 496-499, 530-531 wind, 345-348 types, 121-123 high humidity in the ABL, 499-502 African easterly jet, creation by, 611 emagram, 119-123, 127, 152 instability (nonlocal conditional), 503-508 advection of vorticity (cyclogenesis), 456-462 P vs. alpha diagram, 121 trigger mechanisms causing lifting, 522-526 case study, 348-349 pseudoadiabatic diagram, 121-123, 153 wind shear in the environment, 509-521 components, 347 skew-T log-P diagram, 121-125, 154, 157 convective inhibition (CIN), 522-526, 530-531 cyclone propagation direction, 469 Stüve diagram, 121-123, 153 Coriolis force, effect on, 490-492 direction, 347-348 tephigram, 121-123, 155 CPTP = cloud physics thunder parameter, 530 effect, 345-346, 352 T - log P (emagram), 119-123, 127, 152 , 161-162 magnitude, 347 theta-height diagram, 121-123, 156, 158 daily cycle, 528 wind relationship, 345-349 unsaturated air, 128 damage scales, tornado, 579-580 in hurricanes, 621-623 wind, plotted on, 510 derecho, 491, 494 thermal wind, 346-348 thermodynamic development, 484-485 thickness, 345-346, 436 method of mixed layer growth, 394-395, 697-698 difficulties in forecasting, 527-528, 547 thermally driven circulations, 341-342, 648-657 state, defined, 6 direction (see movement), 516-520 anabatic wind, 649-652 density, 10 downbursts and gust fronts, 554-562 direct, 351, 412 on a thermo diagram, 128 downdraft CAPE, 530-531, 557-559 hydrostatic, 341-342 pressure, 7 evaporative cooling, 556 katabatic wind, 652-653 temperature, 6 gust fronts, 560-563 monsoons, 356 within a hurricane, 624-625 precipitation drag, 555 sea-breeze, 654-657 thermodynamics pressure perturbation, 559-560 thermals, 68, 648-649 first law of, 53, 58-59, 64-65 radar observations of, 253 thermister, 78 frontogenesis, 411 downdraft CAPE (DCAPE), 530-531, 557-559 thermocline, 610 heat, 53-86 downdrafts, 483, 492-494 thermocouple, 78 hurricane, 620-625 duration/lifetime, 486 thermo diagram (see thermodynamic diagram), 119- thunderstorm, 496-508, 522-526 echo-free vault, 493 158 topics, 1 effective thermodynamic diagram, 63, 119-158 thermohaline circulations in ocean, 804 bulk shear, 522 airmass modification over mountains, 398-399 thermometers, 75, 78-79, 219 bulk wind difference, 522 applications, 127-133 thermopause, 13 depth, 522 chinook and foehn winds, 676-677 thermosphere, 12-13 inflow layer & inflow base, 590 blanks, 151-158 thermostat, 78 layer, 522 boundary layer, for, 144, 157-158 theta (q) - (potential temperature), 61-63, 103-106 storm relative helicity (eSRH), 590 building/creating, 119 theta-height (z) thermodynamic diagram, 121- supercell composite parameter (eSCP), 591 cloud base height, 130, 162, 164, 496-498 158 elevated inflow, 522 cloud diagnosis, 134 theta-w vs theta-e, 105 energy helicity index, 530-531 cloud top, 162, 164, 496-498 thickness, 17 energy released by, 499 complete/full/large, 121, 151-158 100 to 50 kPa chart, 346-348, 436, 439, 442 environment, 141, 496-499 components, 119-121 contours, 346-348, 458 pre-storm, 496-531 adiabats, 63, 103 definition, 17, 345-346 equilibrium level (EL; storm top), 497-506 buoyancy, 135-136, 498, 503-508 in high pressure center, 390-391 evolution, 484-485 cloud base, 130, 162, 164, 496-498 of clouds, 161-162 flanking line, 492, 494 dry adiabats, 63, 119-128 on weather maps, 346-348, 436, 439 flow stability, causing, 138 environmental lapse rate, 134-136, 138, 496- optical, 43, 805, 856 flumen (inflow cloud bands), 169 498, 503-508 related to thermal wind, 345-349, 436 forecasting, 527-532, 547 height contours, 121 temperature relationship for, 79 formation conditions, 496-527 isentrope, 63 threads (see end of each chapter) forward-flank downdraft (FFD), 483, 492-493 isobar, 63, 100, 119-128 threat score, 781-782 frequency/activity (isoceraunic), 18 isohume, 100-102, 119-128 equitable, 782 frontal, 400, 525 isotherm, 63, 100, 119-128 three-band general circulation, 329, 376-378 graupel, 493 lifting condensation level, 93-96, 105-107, 130, threshold gust fronts, 494, 554-562 138, 162, 164, 483, 496-501, 522-527, 530- for binary/categorical forecasts, 780 hail, 493, 548-553 531 for probability forecasts, 777 significant hail parameter (SHIP), 530-531 moist adiabats, 102-106, 119-128, 496-499, 503- temperatures for ice nucleation, 195 hazards, 481, 545-602 506, 522-527 thunder, 571-576 heat convective inhibition (CIN) determination, 523- 3-second rule, 575 flux profile, 70-71 526 audibility, 575-576 released, 546-548 dew-point temperature, 128 creation mechanism by lightning, 571 helicity, 587-592 dry (unsaturated) processes, 129 distance away, 576 storm-relative (SRH), 530-531 environment, 134 force of, 571 updraft (UH), 530 excess water, 186 ray paths, 575-576 high-precipitation (HP) supercell, 492, 495 for boundary layer, 157-158 shock wave, 571-574 highs (anticyclones) associated with, 391 humidity, 128 sound wave, 575-576 hook echo, 494 hurricane thermodynamics, 624-625 thunderhead, 482 humidity, 499-502 identifying different types of, 126-127 thundersnow, 207 hurricanes, in, 604, 613-615, 620-621, 637 isohumes of mixing ratio, 100-101 thunderstorm(s), 481-602 hybrid supercell, 492 locate stable layers, 733-734 airmass, 486 in cold fronts, 400, 525 masters, 151-158 altitudes, 496-499 indices for forecasting, 530-531 misinterpretation, 729 appearance, 482 inflow bands (flumen), 169 mixing ratio, 128 aspect ratio of, 485 inflow of humid air from ABL, 546-547 moist (saturated) processes and liquid water, attributes, 481-495 influence on mixed layer, 510 101-106, 129 base at LCL, 497-498 instability, 496-508 mountains, lifting over, 398-399 elevated inflow, 522 intensity forecasting, 501, 507, 516, 521-522, 524, parcels vs environment, 134 basic, 486-487 530-531 partial water fallout from clouds, 130-131 bear’s cage, 495 key altitudes, 496-499 plotting on, 128 beaver-tail cloud, 492, 494-495 latent heating inside, 546-548 pressure, 128 bookend vortex, 490-491 level of free convection (LFC), 497-506, 530 T R. STULL • PRACTICAL METEOROLOGY 919

lifting condensation level (LCL; storm base), 497- top blowdown of trees, 593 506, 530-531 cold, 546 boundary layer of, 586 lifting needed to trigger, 522-527 equilibrium level (EL), 498 breakdown bubble, 592-593 lightning and thunder, 563-576 tornadoes, 494, 577-593 bulk Richardson number shear, 522 global lightning mapper, 235 significant tornado parameter (STP), 530-531 Burgers-Rott vortex (BRV), 599 limit of convection (LOC; see equil. level), 498 triggering, 496, 522-526 change criterion for SPECI, 270 line-end vortices, 490 tropical, 331-332, 350-351 cold-air funnels, 582 long-lasting, 509-510 tropopause vs. storm top, 496-506 cone shape, 577 low-precipitation (LP) supercell, 492, 495 turbulence (see updrafts & downbursts), 111, core pressure deficit, 577-578 main updraft, 483, 492, 495 508, 527-530 cylinder shaped, 577 MCC (see mesoscale convective complex), 491 types, 486-495 damage MCS (see mesoscale convective system), 488-492 UH = updraft helicity, 530 exploding houses, 674 mesocyclone, 481, 483, 492-495, 510, 582, 586-591 unfavorable conditions for, 499 paths, 584 meso-high, 391, 488 updrafts, 483, 498, 503-508, 649 scales, 579-580 meso-low, 489 helicity (UH), 530 debris cloud, 581-583 mesoscale convective upslope, 526 developing stage, 583 complex (MCC), 491 vault (echo-free), 493 dissipating, 583 systems (MCS), 488-492 venting of boundary layer air, 691-692 dust swirl, 583 vortex (MCV), 492 violent, 492, 498 evolution, 583 midlatitude-cyclone related, 425-428, 434, 438, warming rate due to condensation, 546 family, 584 466 warnings and watches, 528-530 forecasting, indices for, 530-531, 588-592 mixed layer, 496-503 watch-box, 528-529 frequency in USA & Canada, 579 movement, 483, 510 weak echo region (WER), 493 funnel cloud, 483, 581-583 normal storm motion, 516-518 weakly forced (airmass), 486 hourglass shaped, 577 left- and right-moving, 518-520 weather-map symbols, 275-276, 481 in hurricanes, 584, 627, 637 multicell, 486-487 wind shear in pre-storm environment, 509-521 intensity scales, 579-580 murus (), 170 Tibetan low, 354-356 enhanced Fujita (EF) scale, 578-580 nighttime, 590 TIBL (thermal internal boundary layer), 654-657 forecasting, 501, 507-508, 516, 522, 530-531 nonlocal conditional instability (NCI), 498, 503- tidal bulge of solid earth, 229 Fujita (F) scale, 579 508 tides, lunar and solar, 376, 635 Torro (T) scale, 579-580 organization, 486-495 tight packing of isopleths, 143 irrotational winds around, 385 orographic, 487, 526, 547-548 tiling method for finding CAPE & CIN areas, 504- landspouts, 582 outflow winds, 560-562 505, 524 life cycle, 583 outlook forecasts of convection, 528-530 tilt of likelihood, 591 overshooting dome (penetrative convection), earth axis (obliquity), 30, 798-803, 879 mature stage, 583 498 variations and climate, 798-803 mesocyclones and helicity, 582, 587-592 parameterization in NWP models, 751 high pressure with altitude, 390-391 multiple vortex, 592-593 path (see movement), 516-520 low-pressure with altitude, 432 origin of rotation, 586-587 precipitation, 206, 486, 493, 495, 545-554 mountain waves with altitude, 668 outbreaks, 583-584 precursor clouds (altocumulus castellanus), 165 troughts with altitude, 432 in hurricanes, 637 tilted intensity scales, 579-580 pressure perturbations, 559 coordinate system, 124-125, 650-653 origin of rotation, 586-587 propagation of, 485, 494 isobars, 345-349, 359 pressure pulse, 486 tilting decrease in core, 577-578 radar images of, 243, 248, 253-254, 482-483, 486- effect on frontal zone strength, 409 increase due to wind stagnation, 672-674 488, 490-495, 552-553 of cold-core cyclone, 622 Rankine combined vortex wind model, 577-578, radiative effects, 131-133, 624-625 of front, 412 599 rain, heavy, 545-548 of tropopause, 415 reports, 532 rainfall rate, 546 of trough, role in cyclogenesis, 432, 622 rope shape/stage, 577, 583 random effects in thunderstorm development, of vertical temp gradient, 409 rotation, 577-578 527 of wave crests with altitude, 668 direction, 578-579, 586 rear-flank downdraft (RFD), 492-494 term in vertical vorticity eqn, 447-448, 586-587 origin, 586-587 rear inflow jet (RIJ), 489 time, 870 safety, 583-584 risk of, 528-530 airmass thickness, max, 395 scales, 579-580 rotation, 586-591 astronomical values that determine time, 34 shapes, 577 safety, 485, 517, 567, 570, 575, 583-584 constant (isochrone), 18 significant vs. weak, 501, 507-508, 516, 522, 530- satellite images of, 234 daylight (summer), 5 531, 580 sequence of events, 484 differencing in NWP, 757 significant tornado parameter (STP), 530-531, severe thunderstorm e-folding, 9, 393-396 592 definition, 528 equation of, 34 spin-up, 586-587 environment, 496-502 GMT, 5 stages in evolution, 583 watches and warnings, 528-530 isochrone, 18 suction vortices, 592-593 severity forecasting, 501, 507, 516, 521-522, 524, lead, 762 supercell, 582 530-531 line, numerical, 757 swirl ratio, 530-531, 592-593 significant hail parameter (SHIP), 530-531 scales, 315 tangential velocity vs. intensity, 577-580 significant tornado parameter (STP), 530-531 Lagrangian turbulence, 732 thunderstorms, relationship to, 577 single-cell, 486 standard, defined, 5 total speed, 578 size, 481-498 step, 750 translation speed, 578, 582 soundings, pre-storm environmental, 496-499 sunrise & sunset, 33-34 types, 582-583 squall line, 243, 488, 490, 582 twilight starts and ends, 33-34 V-shaped, 577 SR (storm relative), 584 units, 870 vortex signature, 251, 253, 599 winds, statistics for, 585 UTC, defined, 5 vortices that are not tornadoes, 582-583 stability indices, 530-531 valid, 762 dust devils, 582 stages of evolution, 485 zones, defined, 5 gustnadoes, 582 storm-relative helicity (SRH), 530-531, 590 Zulu, defined, 5 steam devils, 583 straight-line winds, 489-490, 554, 560-563 tipping bucket rain gauge, 210 firewhirls, 583 derecho, 491, 494 tips for doing homework exercises, 20-26 wall cloud (murus), 170, 483 stratiform clouds, 488-489, 492 TIROS (Television and Infrared Operational System), watches and warnings, 528-530 strength forecasting, 501, 507, 516, 521-522, 524, 273 waterspouts, 582 530-531 TKE (see turbulence kinetic energy), 708-710 weather-map symbols, 276 supercell, 482-484, 492-495, 549, 553 Toba, Lake, 805 wedge, 577 composite parameter (SCP), 530-531 tongue, dry air, 429 winds effective (eSCP), 591 tonne mass units (or metric ton), 870 cyclostrophic, 311-312 tornadoes, 577, 582 tools, scientific, 877 dynamic warming, 673 wind statistics, 585 top of exploding houses, 674 steering-level winds, 487 atmosphere, observations of, 220 irrotational, 385, 577 suppression of neighboring storms, 547 clouds, 162 torque on swirl ratio, 530-531, 592-593 mixed layer, 497 atmosphere, 366 symbols on weather maps, 275-276, 481 thunderstorm (equilibrium level, EL), 497 Earth, 376 tail cloud (cauda), 169 topographic formation of highs, 391 satellite orbit, 229 thunder, 571-576 tornado, 483, 494, 577-593 Torr, 7 timing, 528, 546 appearance, 581-583 TORRO scale for effect of mountains on, 528 bait, 592 hailstone diameter, 548 920 INDEX T

tornado intensity (T), 579-580 planetary waves, by, 374-375 axis, 281, 367 total mixed layer coefficient, 68 of cyclone case study, 433 deformation, 321 momentum, global, 375-376 symbols on weather map, 281, 399 derivative, 872 turbulent, 709 circumpolar, 432 entropy, 624-625 of heat, 67-71 formation & characteristics, 367-376 meridional heat transport, 378 of moisture, 109-111 in tropical easterly waves, 611-612 shear magnitude, 515-516 velocity of turbulence, 300 in Rossby waves, 353, 367-376 distribution of, 515 transverse (cross-frontal) circulation, 412, 415 monsoon (MT), 612 solar irradiance (TSI), 39, 793-794 trapped low-level barrier jet, 664-665 tilt with altitude, 432 variations, 803 trapping of tropical upper-tropospheric (TUTT), 612-613 totals index (TT), 531 pollutants, 725 upper-level disturbance, 433 water, 94, 97-99 radar beam, 244-245 TROWAL (trough of warm air aloft), 281, 399, 413- conservation of, 99-111 tree 414 content in a column of air, 211 blowdown by downbursts & tornadoes, 593 true fallout from cloud, 108 ring dating (dendrochronology), 803 anomaly, 29, 802 in fogs, 176 Trenberth omega equation (see omega equation), longitude, 802 in thermo diagram, 128-133 456-458 skill score, 781 mixing ratio, 97-99, 186 Trenberth, Kevin, 339, 458, 797 truncation error, 754-755, 760 reduction in thermo diagrams, 130-133, 397- omega equation, 458 trunk space, 677-678 398, 676 triangle shaped ice crystals, 199 TSI = total solar irradiance, 39-45 TOVS (TIROS Operational vertical sounder), 273 Tricker arc, 854-855 tuba, 169 tower trigger mechanisms for tumble of small falling ice crystals, 842 hot convective, 644 hurricanes, 610-613 turbine, wind updraft, 482 thunderstorms, 485, 496, 522-526 efficiencies, 647-648 towering cumulus (tcu), 162, 168, 483 trigonometric conversions, 650 pressure change across, 671 stage of thunderstorm-cell evolution, 485 trimming data, 826 turbulence, 705-716 toy model(s) of, 330 triple point, 414 atmospheric boundary layer (ABL), 687, 705-716 airmass formation, 393-396 trof (see trough) above ABL, 110, 687 climate processes, 793-796 trop (see tropopause) airmass characteristics of, 391-396 differential heating (global), 334-339 Tropic of role in evolution, 393-396 extratropical cyclone, 450-451 Cancer, 31 buoyant, 704, 705 global circulation, 330-334 Capricorn, 31 generation, 709-710 hurricanes, 626-629 tropical cascade, 315 jet stream, 359-360 airmass clear-air (CAT), 141-142, 165 MSL pressure tendency, 464-467 code, 392 closure, 713-716 transmittance of radiation, 225-226 genesis, 393-395 closure types, 714-716 trace cloud heights, 163 K-theory, 714-716 matrix, 822 convection variations due to ENSO & PDO, 820 transilient turbulence theory, 716 rainfall rate, 208 convergence clouds created by, 165-166 tracers, passive, conservative, 731 in easterly waves, 611-612 conservation, 706, 708-709 TRACKOB code, 269 zone (ITCZ), 330-332, 351, 610-612 covariances, 711-713 tracks cyclogenesis (birth of hurricanes), 608-610 convection extratropical cyclones (lows), 429-431 cyclolysis (death of hurricanes), 616 forced, 710 tropical cyclones (hurricanes), 607-608, 615 cyclones (see hurricanes), 330, 427, 603-644 free, 710 thunderstorms and tornadoes, 483, 516-520, 584, cumulus, 351 convective, 705 593 depression, 613-614 mixed-layer, 704 trade disturbance, 613 thunderstorm, 508, 527-530 inversion, 351 easterly jet and waves, 611-612 correlation coefficients, 711-713 winds, 330-332, 351 forecasters/meteorologists, 343, 611, 613 defined, 705 cumuli, 351 geostrophic & gradient winds, 611-612 determination, 138-142 role in steering hurricanes, 607-608, 615 hurricane, 603-644 dispersion of pollutants, caused by, 723-744 role in triggering hurricanes, 610-612 monsoon, 333-334, 356, 612 dissipation, 706, 709 Walker circulation, 820 Prediction Center, 638 existence, 142 trading, emissions, 742 rainfall, 209-211, 351 fair-weather, 69-70 trajectories, 668-669 storm, 614-615, 635-636 flux backward, 724 watches & warnings, 638 as a covariance, 711-713 forward, 724 streamlines, 611-612 from advection terms, 714 of hailstones, altering, 553-554 thunderstorms, 331-332, 351-352 divergence terms, 747 path lines, 669 trade inversion, 351 gradient, 65, 67-71, 107-111, 698, 711-716, 746- transfer of electric charge, 564-566 trade winds, 331, 351, 358, 376, 610, 612, 615 747 transformations: inertial or Newtonian, 715 tropopause, 163 heat, 711-714 transilient turbulence theory (T3), 714, 716 typhoon (see hurricanes), 603-644 momentum, 713 transition upper tropospheric trough (TUTT), 612-613 forced convection, 710 hurricane extratropical, 615 winds, 611-612 free convective/convection, 704, 710 winds: anabatic vs. katabatic, 654 year, 31 heat budget, in, 69, 713-716 translation of tropics, 330 heat flux, 711-712 hurricanes, 627-628 intertropical convergence zone (ITCZ), 233 in air masses, 397-398, 691-692 thunderstorms, 516-520 tropopause, 12-13, 414-415 in cloud tornadoes, 578, 582 folding rotor clouds, 165 translucent, 42 fronts, upper-level, 414-415 thunderstorms, 481-602 translucidus, 169 isentropic potential vorticity, 364, 441-443 in neutral static stability transistors, 752 of cyclone case study, 441-443 inertial subrange of, 708 transmission of radiation, 41-43 on weather maps, 364, 441-443 intensity, 710 transmissivity, 42 ozone injection by, 364, 414-415 intermittent, 692 net sky, 44 radionuclide injection by, 364, 414-415 isotropy, 707, 710 transmittance of atmosphere, 220-226 satellite observations of, 234 kinetic energy (TKE), 708 profiles, 225-226 height, 143 advection, 708 transmitted solar radiation, 805, 856-858 determination, 143, 496 budget equation, 708 transparency of variation with latitude, 163, 353 buoyant production or consumption, 709 atmosphere, 220-223 pressure, 163 cascade, 315 reduction due to volcanic eruptions, 805 thunderstorm tops near, 497-498 dissipation, 709 clouds, 169 winds near (also see jet stream), 331-332, 357-362 generation, 708-709 windows on radiometers, 45 troposphere, 12-13 shear generation, 708-709 transpired (CO2 from plants), 812 average density, 72 tendency, 708 transport average depth, 12 mean and turbulent parts, 705-706 coefficients coupling with daily heating cycle, 687-692 mechanical, 704, 705 bulk heat, 68 depth, 12, 143 microscale, 708 bulk moisture, 109 variation with latitude, 163 momentum flux, 713 convective coefficient, 68, 109 folds, 364, 414-415 mountain wave, 667 Ekman, hurricane, 610, 633-634 upper trough, tropical (TUTT), 612-613 onset, 142 energy, 53, 499-502, 708-709 tropospheric constraints on atmos. boundary layer, parameterization in NWP models, 751 heat, 68 689-690 production, 708-709 global, 338-339 trough(s) (see also midlatitude), 332 scales of motion, 315 T, U, V R. STULL • PRACTICAL METEOROLOGY 921

radar observations of CAT, 242 uncontrolled experiments, 554 divergence radar spectrum width in, 254 understanding & critical evaluation, exercises ex- due to jet streak ageostrophic flow, 454-456 raindrop growth affected by, 206 plained, 23 due to jet stream curvature, 453 scales of motion, 315 undulatus, 169 related to pressure tendency, 464-467 shear, 704, 705 undular bore (roll cloud), 169 fronts, 414-415 generation, 708-710 unidata IDV, 772 trough, position that causes cyclogenesis, 432, stability dependence, 119, 138-142, 688, 707-708, United Nations, 268 450-453, 467 710 units, 870 winds, 331-332 stably-stratified (SST), 710 component of scientific notation, 870 upper stationary, 708 concentration of pollutants, 724 atmosphere, 13 statistics, 706-708, 726-728 conversion, 871 quartile, 502 stormy-weather, 70-71 density, 10 suncave Parry arc, 854-855 terms, derivation, 714 force per mass, 292-300 sunvex Parry arc, 854-855 thermal, 134-140, 144, 648-657, 704, 708-710, 716 metric (SI), 7, 870 tangent arcs, 842, 851-855 thunderstorm, 111, 508, 527-530 MKS system, International System (SI), 7, 870 tropospheric transilient, 714-716 potential vorticity (PVU), 364 fronts, 414-415 transport, 300, 709 pressure, 7, 19 winds, 331-332 types, Pasquill-Gifford, 727-728 scientific, 8, 870 Wegener arc, 855 velocity scales, 68-69 temperature, 7, 870 upside-down cold thermals, 177 wake, behind mountains, 667 water vapor pressure, 87 upslope turbulent universal flow (anabatic), 649-652 continuity equation, in flux form, 714 constants, 879 fog, 173 convective mixing, 69-71, 108-111, 138-139, 144, observation codes, 268 rain, 398-399 704, 710, 735-737 theories, 107, 877 thunderstorms, 526 dispersion of pollutants, 724 universities and NWP, 772 upward motion drag, 300 unsaturated (see also dry), 57, 87, 92 at cold fronts, 470-471 above the boundary layer, 300, 687-690 air, 87 in extratropical cyclones, 425, 451-462 atmospheric boundary layer, 300, 699-701 air parcel, 128-129 upward velocity in extratropical cyclones, 425, 426, force, 300-301 definition, 87 451-462 term in vertical vorticity equation, 447-448, heat budget, 57 upwelling 586 humidity, 87-96 ocean water in hurricanes, 610 eddies, 706, 708 lapse rate, 60, 129 radiation, 44-45, 220 flow, 660, 705 unstable urban heat flux, effective, 68 absolutely, 140 breezes, 679 flux air (regions), 138-139, 688-689 canopy, 678-679 divergence, 715 clouds in, 161-162, 164-165 canyon, 678-679 variation with height, 70, 698, 715-716 dispersion of smoke in, 710 cloud formation over, 162 gusts, 705-706 determining, 138-139 heat island, 678-679 kinematic moisture flux, 108-109 velocity standard deviations, 707 plume, 678-679, 742 kinematic heat flux, 68 atmospheric boundary layer (ABL), 692 smog, 193 mixing turbulence, 707-710 U.S. (USA) frontolysis, 411 baroclinically, 371 air quality standards, 725 by thunderstorms, 70-71, 111 barotropically, 368 geography, 431 parts, 705-706 boundary-layer wind, 308 Joint Typhoon Warning Center, 607 Reynolds stress, 701 conditionally, 140-141, 498 National Hurricane Center (NHC), 608, 638 stress, 701 nonlocal, 496-499, 503-508 National Inst. for Standards & Tech. (NIST), 51, surface layer, 709 drag, turbulent, 300 879 transport, 709 dry absolutely, 140 national lightning detection network (NLDN), of heat, 67-71 equilibrium of droplets, 191 568-569 of moisture, 109-111 flow, definition, 138 National Oceanic & Atmos. Admin. (NOAA), transport velocity, 300 mixed layer, 692 637 velocity variances, 706-708 nonlocally, 138-144 National Weather Service (NWS), 532 vertical heat flux divergence, 64-65, 69-71, 698, conditionally, 496-499, 503-508 short scale number prefixes, 870 711-716 saturated absolutely, 140 standard atmosphere, 11-13 wake, 165, 667 statically, 138, 688-689 states & their postal abbreviations, 431 whirls (eddies), 708 cumulus cloud formation in, 162 Storm Prediction Center, 532 turret (shaped clouds), 168 up, definition of, 4, 298 Supreme Court, quotation, 470 TUTT (tropical upper tropospheric trough), 612-613 updateable MOS (model output statistics), 771 symbols for clouds on weather maps, 168 updraft(s) Tropical Prediction Center, 638 TV (television), severe weather reporting, 529-532 bubble, 482 usage of probability scores for forecasts, 785 TVS = tornado vortex signature, 253, 599 cloud, 162 UTC (Coordinated Universal Time), 5, 268 twilight, 11, 33-34 helicity (UH), 530 uv (see ultraviolet), 222 astronomical, civil & military, 33-34 main, 483 twinned rainbows, 841 rotating, 492 twister (see tornado), 577-593 , instability & CAPE in thunderstorms, 503-508 two-layer system of fluids, 657-661 thermals, 648-649 two-way nesting of NWP grids, 752 tower, 482 V types of velocity in V shaped tornado, 577 clouds, 168-169 cyclones, 446, 451-462 V time zone (Alaska), defined, 5 fog, 173 easterly waves, 612 V-velocity definition, 2, 3 thunderstorms, 486-495 hurricanes, 605, 612, 620, 628 determination using hodographs, 513 typhoons (see hurricanes), 330, 426, 603-644 of buoyant thermals, 648-649 vacuum, 19 damage potential (CDP), 607 thunderstorms, 508, 649 speed of light in, 834 international forecast organizations, 607 upper-air VAD = velocity azimuth display, 252-253 intensity scales, 607 jet Väisälä (in Brunt-Väisälä frequency), 136-137 super- , 607 streaks, 454-456 valid time, 762 streams, 357-361, 405-407, 414-415, 452-453 valley mandatory levels, 134, 772 circulations, 649-654, 660-670, 675-676 significant levels, 134, 147 fog, 177 soundings, 134 gap winds, 661-664 U locations worldwide, 271 pollutants trapped in, 654 U time zone (Pacific), defined, 5 Pacific data void, 288 subsidence into, 654 u* (see friction velocity), 378, 700-704, 709 weather maps and charts, 291 winds, 649-654, 660-670, 675-676 U velocity definition, 2, 3 winds vs. thunderstorm strength, 510 value determination using hodographs, 513 upper-level components in scientific notation, 870 UHF = ultra high frequencies, 259 charts, in case-study of cyclone, 433-466 of forecasts, economic, 784-785 UK air quality objectives, 725 reason for using, 291, 436-437, 442 Vancouver ultrafine aerosols, 188 20 kPa, 440-443, 452, 455-456 International Airport (CYVR), 646-647 ultrasonic snow depth sensor, 210 50 kPa, 433, 442, 448, 451 solar azimuth & elevation, 32-33 ultraviolet light (see also radiation), 222, 857 70 kPa, 439, 442 vanes, wind, 219, 321 haze filters for cameras, 857 85 kPa, 439, 442, 449, 459-462 van’t Hoff factor, 190 uncertainty in weather forecasts, 776 100 kPa, 438, 463 vapor pressure, 14, 87 uncinus/unc, 168 disturbance, 433 definition, 87 922 INDEX V

over curved droplets, 189-192 angle from Earth, 802 vs. cloud droplet for diffraction fringes, 858-860 over flat surface of water, 87-90 vertebratus, 169 violent stage of thunderstorms, 485 reference, 88, 880 vertical violet color defined (also see optics chapter), 37 saturation, 87-90 advection of virga, 169, 185, 482-484, 547 supersaturation, 186 heat, 67, 72, 714 weather-map symbol for, 276 units, 87 mass, 317-318 virtual variation with temperature, 14, 88 momentum, 295, 315 potential temperature, 61-62 vapor, water feedback, climate, 810 vorticity, 447-448 in buoyancy, 135-136 vaporization, latent heat of, 54, 56, 88-90, 108, 880 axis on graphs, 3 in downbursts & DCAPE, 555-563 variance, 706, 727 cell circulation, 377 in katabatic flow, 649-653 smoke plume spread, 726-732, 735-737 circulations (global), 332-333, 377-378 temperature velocity, 706-708, 727 effective, 377-378 average, as measure of thickness, 17-18 variable(s) component of the equations of motion, 315-317 constant, 14-15, 880 conserved, 61 coordinates, alternative, 746 defined, 14-15 continuous, verification of, 777-780 cross section of in buoyancy, 135-136 dependent, 872 atmosphere, 143-144, 332, 357, 359, 373, 432 in CAPE, 503-504 independent, 872 cyclone (case study), 441 in gust fronts, 562-563 gases in the atmosphere, 7 dry line, 416 vis5D, 772 grids and grid meshes, 752-753 fronts, 403-407, 412-416 viscosity, eddy, 715 italicized notation for, 870 hurricanes, 605, 618, 620-621, 624, 629 viscous dissipation rate of TKE, 315, 709 variant pi, 801 storm surge, 632-635 scales, 315 variational data assimilation (3DVar & 4DVar), 273, thunderstorms, 482-490, 496, 510, 525-526, visibility, 43, 170, 270, 275, 867 767 553-554, 563, 566, 575 airmass characteristics, 391 varieties of clouds, 168-169 troughs, 432 change criterion for SPECI, 270 vault, echo-free, 493, 552-553 density profile, 10 definition, 43, 867 vector direction, 4 haze, 193, 856-858 equation, 292 equation of motion, 315-317, 746 in precipitation, 208-209 force , 292 applied to thunderstorms, 649, 554 METAR, 270 operators for thermals, 649 minimum (in METAR), 270 cross product, 299 flux divergence, 65-73, 109-110, 746 reduced, 170, 193, 270, 275 dot product, 239 flux of water vapor, 108 runway visual range (RVR), 270 sum, 292 during free convection , 109-110 weather-map codes, 275 wind forces as cause vertical motion, 315-317 vertical, 170 difference (surrogate for shear), 509 frontal structure, 403-404 visible shear, 509 gradient, 872 light, 220, 222 velocity, 292, 509 geostrophic wind (thermal wind), 345-349 satellite images (photos), 230-233 veering wind, due to warm-air advection, 349, 511, IR flux, 71 visual 520 mixing ratio, 75, 110, 692 geometric albedo, 879 vegetation potential temperature, 67, 75, 110, 688, 690, range (also see runway visual range, RVR), 43 greenness, 230, 751 692, 695-698 visualization programs for NWP output, 772 parameterizations, 749-751 pressure, 8-9, 12-13, 15-17, 554, 621-623 void, Pacific data, 287-288 veils of clouds, 168 mean temperature advection, 72 volatile hydrocarbons, 193 velocity (see also speed), 2-3 motion, 66, 451-462 volcanic azimuth display, 252-253 omega, 451, 456-462 ash & aerosols, 170, 276, 804-805, 858 buoyancy scale, 68-69, 110, 704 pressure gradient, 15 climate change processes, 804-805, 810 components, 2-3, 293, 314-315, 746 profiles, 119 eruption(s), 804-805 convective, 68-69, 704 pressure, 9 Agung, 805 Deardorff, 69, 703-704 potential temperature, 67, 75, 110, 688, 690, change criterion for SPECI, 270 downburst, 554-557 692, 695-698 Cotopaxi, 805 entrainment, 697-698 weather variables, 119, 134 Deccan traps, 805 friction, 378, 677, 700-713 shear, 509-521, 699-704 El Chichon group, 658 structure Krakatau, 805 horizontal, 2-3 anticyclone (highs), 391 Lake Toba, 805 scales, buoyant, 68-69, 109, 300, 703-704 atmosphere, 11-13 Mt. Tambora, 805 scales, mechanical, 68-69, 109, 700-703, 708- cold front, 403-404 Pinatubo, 805 709 warm front, 403-404 Santa Maria, 805 hurricane temperature gradient definition, 872 Siberian traps, 805 radial, 627-628 turbulent flux, 67-71, 108-111, 711-716 Yellowstone caldera, 805 tangential, 605-607, 622-623, 626-627 velocity, 2-3, 252, 448, 451-462, 628-629, 746 red skies caused by, 858 vertical, 628-629 constant, 17 winter, 805 mean wind, 705-706, 726-727 continuity effects that drive, 452-459 The Year Without Summer, 805 of air parcel relative to earth, 360-361 cyclones, in extratropical, 446, 451-462 volcanism influences on climate, 804-805, 810 phase, 658 downbursts, in, 554-562 volt, unit of electric potential, 564, 870 radial, 249-254 equations for, 315-320 voltage breakdown potential in air, 566 standard deviation, 706-708, 727, 731-732 hurricane model, 628-629 voltage difference, 564-566 tangential omega, 451, 456-459, 462 volume in hurricane, 605-607, 622-623, 626-627 Q-vectors, 460-462, 469-471 density, 10 in tornado, 577-580 radar, 252-253 extinction coefficient, 43 terminal, 202-204, 555 standard deviation, 706-711, 731-732 fraction of gases in air, 7 thermals, 649 subsidence, 545-546 grid, 750-756 thunderstorm updrafts, 508 synoptic scale, 448 sampled by radar, 240 tornado, 577-580 thermals, in, 649 scans by radar, 241 turbulent transport, 68-69, 109, 300, 703-704 thunderstorms, in, 508, 545-546, 557-559 specific, 10 variance, 706-708, 727, 731-732 top of boundary layer, 319-320 isostere, 18 vertical, 2-3, 252, 448, 451-462, 628-629, 746 top of hurricane, 612, 618, 628 von max up- and down-drafts, 508, 557-559 typical, 318 Freiberg, Theodoric, 841 omega, 451, 456-462 vorticity, effect of, 448 Goethe, 249 Q-vectors, 460-462, 469-471 weather map of, 448 Kármán constant, 677, 701 wave, 658 visibility, 170 Neumann, John, 624, 669, 749, 759 winds, summary of, 314 wave propagation, 668 vort max (see also vorticity maximum), 457 velum, 169 wind speed, 318, 451-462 vortex / vortices venting of atmos. boundary layer air, 691-692 Ekman pumping, 319-320 book-end, 490-491 venturi effect , 674-675 isanabat, 18 Burgers-Rott (BRV), 599 verification of forecasts, 777-785 thermals, 648-649 cold-air funnels, 582 binary variables, 780-782 very debris cloud, 581 categorical events, 780-782 fine particulate matter (PM2.5), 725 , 582 continuous variables, 777-780 low frequency (VLF) radio waves, 568 firewhirl, 582 cost-loss decision models, 784-785 VHF = very high frequencies, 258-259 funnel cloud, 581 probabilistic forecasts, 782-784 vibration lines is spectra, 221 gustnado, 582 scores, 752, 777-785 vicinity, weather map symbol for, 276 landspouts, 582 verifying analysis, 769, 777 viewing angle, 838, 846 line-end, 490 vernal equinox (Spring), 30-31, 801-802 for rainbow rays, 839-840 mountain-lee, 165 angle from perihelion, variation of, 799-801 minimum, 846 multiple-vortex tornadoes, 592-593 V, W R. STULL • PRACTICAL METEOROLOGY 923

polar, 397, 824 clouds at, 162-164 watt, unit of power, 870 Rankine combined, 577-578, 599 definition, 404 wave, 705 roll, horizontal, 167 drizzle from, 546 African easterly wave, 611-612 spray, 582 extratropical cyclones, attached to, 425-428 amplitude, 368-374, 443-444, 634, 666-668 , 582 halos , 401, 842 atmospheric, 705, 710 stretching, 447-451, 586 horizontal structure, 401 battering of structures by ocean waves, 634-635 suction, 593 horizontal winds, 401 bore, 656 tornado, 577-593 occlusion, 413-414 boundary layer, 710 signature (TVS) on Doppler radar, 253, 599 rain from, 546 buoyancy, 666-668, 710 supercell, 582 stratiform clouds, 162-164, 401, 425-428 thunderstorm triggering, 526 tube, 166, 447, 518, 586-587 sundogs, 401, 842 chaotic clouds, 169 waterspouts, 582 thunderstorm triggers, 525 clouds (see lenticular, or standing lenticular), wing-tip, 166 weather map symbol, 281, 399 165, 168, 666-667 vorticity, 320-321, 362-365 wind shifts, 401 chaotic (asperitas), 169 absolute vorticity, 363, 448 low-pressure centers, 621-623 optics caused by, 859-860 advection, 447-451, 458 mode rainfall estimates, 257 roll cloud (undular bore wave), 169 PVA & NVA, 447-448, 459 rain, 115 crests, 658, 668 beta effect, 447-451 sector, 425-428 tilt with altitude, 668 cascade, 586 vs. cold core cyclones, 622 curvature, 375 charts, for case-study cyclone, 439-441, 448 winds, 66, 349, 511, 520, 676 definition, 705 circulation, 365-366 warming drag, 668 conservation, 363, 397, 445 dynamic, 672-674 parameterization in NWP, 751 curvature-induced, 362 global (climate), 150, 796 easterly, 611-612 cyclogenesis indicator, 426 thunderstorm latent heat release, 546-548 electromagnetic, 219 cyclonic, along fronts, 407 warnings (forecasts) energy, 658 definition, 320-321, 362-365 hurricane, 631, 638 equations, 368-374, 634, 666 divergence effect, 447-449 thunderstorm/severe-storm, 528-530 flux of heat meridionally, 375 drag effect, 447-449 tropical storm, 638 effect on circulation, 377 forecast equation for, 447-449 watches (forecasts), 528-530, 638 formation in jet stream, 357, 367-376, 443-445 frontal, 407 water, 87-118 fronts/frontal, 427-428, 837, 859 geostrophic, 319, 449-451 availability for droplet formation, 186-187 gravity, 666-668, 710 relative, 319 barometer, 7 thunderstorm triggering, 526 helicity, 587-592 budget, 99-111 group speed, 658 horizontal (streamwise), 518 at surface, 108-109 heat transport by Rossby waves, 374-375, 378 advection, 447-449 Eulerian, 107-111 height of ocean waves, 634-636 circulation, 365-366 Lagrangian, 99-101 interfacial (surface), 658 hurricane environment, 610 thunderstorm, 547 internal, 658 isentropic potential vorticity, 364-365 total water, 99-100 intrinsic phase speed, 658 maximum (vort max), 457 zonally averaged, 210 jet stream (Rossby), 367-376 of cyclone case study, 459 characteristics, constants, and parameters, 880 Kelvin, in ocean, 633-634 on weather maps, 457-458 conservation, 99-101 Kelvin-Helmholtz, 142, 165, 710 negative advection (NVA), 447-448 content, 97 lee, 666-668 planetary, 363-364 density vs. temperature, 835, 880 long, IR, 37-39, 45, 220-226, 230-239, 751, 794-797, positive advection (PVA), 447-448, 459 depth, constant (isobath), 18 810 potential vorticity, 363-365, 397 depth of constant temperature (isobathytherm), long Rossby, 369 conservation, 445 18 mountain, 666-668 isentropic, 364-365 droplet clouds, 163 drag parameterization in NWP, 751 quasigeostrophic approx., 449-451 in cold airmasses, 393-397 momentum relative vorticity, 319-321, 362-363, 577, 586-588 index of refraction, 834-835 effect on circulation, 377 shear-induced, 362 latent heats, 54 transport by Rossby waves, 375-376 solid body, 363 liquid or density current (bore), 655-656 spin-up, 447-449 content, 97 phase speed, 658-661 streamwise, 518, 587-592 depth, 210-211 planetary (see Rossby waves), 367-376 stretching, 447-451, 586-590 depth vs pressure, 7 prefrontal, 656 swirl ratio, 592-593 loading, 15, 555 propagation, 36, 369-370, 611-612 tendency equation, 447-449, 586 mixing ratio, 15, 97-98 for remote sensing, 219-226 tilting effect, 447-449, 586-588 specific heat, 880 ridge, 443 tornado, 577-578, 586-588 mixing ratio, 15, 75, 91, 97-98 Rossby, 329, 332, 353, 367-376 turbulent drag, 447-449, 586 molecular arrangement & electric charge trans- amplitude & other characteristics, 373-374 vertical advection, 447-449 fer, 565 scour by ocean waves, 634-635 wave, 368 molecule content, 188-189 shallow-water, 658 phases, 198 shape of lightning surge, 569-560 precipitable, 98 short Rossby, 369 reflection from, 838 short, solar, 37-46, 220-223, 230-234, 334-339, 693, saturation vapor pressure, 87-90 793-815 W specific heats, 54, 880 solitary (bore), (volutus cloud), 169, 656 W time zone (Hawaii, Aleutian), defined, 5 supercooled, 186 sound, 219 w* (see Deardorff velocity), 69, 110, 703-704, 736 surface tension, 189, 880 speed (see phase speed), 367-374, 611, 834-837 W-velocity definition, 2, 451 thermo diagram, 99-105 shallow-water, 633, 658 wake turbulence behind mountains, 667 total, 97-100 stationary lee-side Rossby, 443-444 waldsterben (forest death), 742 vapor, 7, 87-118 surf, 635 Walker circulation, 820 absorption of radiation, 221-223 surface, 658 wall channel on satellites, 112, 226, 231 swell, 635 cloud (tornadic), 483, 581-583 cloud feedbacks, 810-811 tilt, 372-376, 611, 668 Foehn, 676-677 density, 91 tops sheared off by hurricane winds, 634 murus, 169 density excess, 198 trough, 443, 658 warm feedback, 810 vapor, 87-118 air gas constant, 88-92, 880 channel of satellites, 226 advection (& veering wind), 66, 349, 511, 520 greenhouse gas, 811 feedback in climate, 810 conveyor belt, 433 holding capacity, 87-90 thunderstorm environment, 499-502 rises, 135 in air, 7 velocity, 658 sector of extratropical cyclone, 425-428 mixing ratio, 89-98 vorticity, 368 airmass formation (genesis), 393-395 molecular weight, 7 westward propagation of, 369-372, 611-612 anafront, 404 pressure, 87 wind-driven ocean, 634-636 cloud precipitation processes, 204-206 specific heats, 880 wavelength(s), 36-37, 221-226, 230, 242-243, 329, 367- conveyor belt, 433 vertical flux, 108-110 376, 427, 468 core system, 426 volcanic eruptions of, 805 bands of visible and IR sensors, 45 of hurricanes, 614, 621-625 waterspout tornadoes, 582 bands for satellite sensors, 222-223, 230 vs. cold core, 426, 622 change criterion for SPECI, 270 natural, 666 frontogenesis, 281, 399 cyclostrophic winds, 311-312 of easterly waves, 611 frontolysis, 281, 399 life cycle, 582 of electromagnetic radiation, 222-223 fronts, 399-401 weather-map symbol for, 276 of light, 36, 222, 834-857 aloft, weather-map symbol for, 281, 399 Watson, Andrew, 813 for different colors, 37, 834-835, 862 924 INDEX W

of max growth rate for Rossby waves, 372 wedge angles, 843, 845-847, 855 rose, 646 of mountain waves, 666 Wegener arc, 854-855 variability in METAR, 270 of planetary Rossby waves, 367, 369 Wegener-Bergeron-Findeisen (WBF) process, 201- dispersion of pollutants, 724 of planetary stationary lee waves, 444 202, 546 Doppler-radar measured, 249-254, 322 of wind waves, ocean, 634-636 Weibull distribution for wind speeds, 645-646 downburst, 554-563 wavelets, 837 weighing rain gauge, 210 downslope, 652-653, 675-677 wavenumber, 36 weighting functions for radiative transfer, 226, 237- storm, 667, 675-677 of Rossby waves, 367, 369 239 driven WAVEOB code, 269 for GOES satellites, 226 by forces, 289-328 WBF (Wegener-Bergeron-Findeisen) process, 201- weights, 15 ocean currents, 610, 632-633, 701 202 air, 8 easterlies, 330-332 weak person, 8, 15 jet (African), 611 echo region (WER), 493 pressure, 7 electrical generation by, 647-648 tornadoes vs. significant, 501, 507, 516, 522, 530- well-mixed fog, 176-177 equations of motion, 301, 314-315, 554, 746-749 531 WER (weak echo region), 493 equatorial, 343 weakly forced (airmass) thunderstorms, 486 west errors, 766 weather, 1 Coast weather, 288, 397-399, 472, 765 exponential profile, 678 altitudes, 143 direction, 2 extratropical cyclonic, 425 analysis Gregory, 765 field, 343 hand (manual; subjective), 280-281 westerlies (winds in global circulation), 331, 353 adjustment to mass field, 344 objective (automated), 765-767 Western Hemisphere, 4 Foehn, 676-677 anomaly (isanomal), 18 defined, 4 forces that drive, 302 anticyclonic, 390 westward tilt, 432 forecast equations, 746 associated with warm katafront, 404 wet-bulb, 94 forest canopy, 677-678 balloon, 134 depression, 94 frontal, 400-407 briefing procedure, 765 globe temperature, 117 gale, 635-636 codes & code modifiers, 268-273, 276 mixing ratio, 95 gap, 661-664 control, 218 potential temperature, 103-106 geostrophic, 663 data sources, 271-273 in fogs, 176 long, 662-664 definition, 1 weather maps of, 500 short, 661-662 forecast(s) temperature, 94, 96, 111 general circulation, 330-334 agencies (Nat. Weather Service NWS), 532 weather maps of, 500 geostrophic wind, 302-304, 343-349 computerized (see numerical), 745-792 what scientists do, 470 African easterly jet, 611 medium-range, 768, 775 whirls, big and little, 708 global circulation, 330-334 numerical, 745-792 whiskers, box-and- (statistics), 539 gradient wind, 304-307, 617-618 topics, 2 whistling through trees and wires, 560 gust duration, 605, 607 forecast models, 751 white, 862 gust-front, 560-563 heirarchy, 768 clouds, 856-858 high-altitude (upper-tropospheric), 330-331 frontal, 400-401 dwarf star, 803 hodograph, for plotting winds, 510-513 glyphs (symbols on weather maps), 276, 282 out (in blowing snow), 208 horizontal, 302-314 highs, in, 390 Wien’s Law, 37 hurricane instruments for measuring Wieringa, Davenport - roughness length classifica- exploding houses, 674 errors of, 875 tion, 700 force winds (Beaufort scale), 635-636 humidity, 97, 111-112, 219 wild fire and CO2 release, 812 radial, 627-628 precipitation, 219 Wilde, Oscar, 523 stages of life cycle, 614 pressure, 19, 219 wind(s), 302-314 tangential, 614, 622, 626-627 temperature, 78-79, 219 ageostrophic, 304, 343, 454-456 idealized, 302-314 radiation, 45-47 anabatic, 649-652 inertial, 312 remotely, 219-266 anemometer, 321-322 oscillation, 304, 311-312, 700 soundings, 134-135 anticyclonic, 306 inflow, 618-619 wind, 219, 321-322 antitriptic, 312-313, 663 instruments for measuring, 321-322 map(s) aspre, 676 pitot-static system, 674 airmass codes, 391-392 austru, 676 irrotational, 385 analysis methods, 274-281, 402 average, global circulation, 330-334, 358 jet stream, 357-362 CAPE, 506-508 barbs on station-plot model, 278, 291 low level, 664-665 case-study examples of, 433-466 Beaufort scale, 635-636 katabatic, 652-653 global pressure patterns, 354-355 Bora, 675-676 local, 645-686 humidity, pre-storm, 500-501 boundary-layer gradient (BLG) wind, 309-311, log wind profile, 677, 702-703 max advection, finding, 458 613-615, 618-619 magnitudes, 314 NWP output, 772 boundary-layer wind, 307-309 mean vs. instantaneous (turbulent), 705-706, 726 solenoids, finding, 458 breeze, 635-636 measuring, 321-322 station plot model, 274-279 canopy, 677-679 height, 701 symbols for cloud genera, 168 ceaseless, 329 METAR, 270 symbols for hurricanes, 614-615 channeled, 664 mountain, 649-654, 660-670, 675-676 symbols for precipitation rate, 208 chill temperature index, 76-77 names of (at steady state), 302, 314, 654 synoptic, 274-281 Chinook, 675-676 near-surface, global, 330-331 thunderstorm environment, 500-501, 506- circulation, 329-388 noise, 560 508, 522-525, 532 coastal, 654-657, 661-665 non-equilibrium, 618-619 vorticity advection, 459 cold-air drainage, 177, 652-653 outflow, 554, 560-563, 618-619 winds on, 290-291 components (U, V, W), 2, 3 plotting on weather maps, 291 METAR, 270 conversion to speed and direction, 2 power, 647-648 observations, 268-273 graphical determination (hodograph), 513 average, 647 at airports , 268-271 conversion, 3 theoretical available, 647-648 locations, 271-273 cyclonic, 306 vs. wind speed, 647-648 METARS, 268-271 cyclostrophic wind, 311-312, 618 profile using satellites, 227-239, 272-273 damage by convective radix layer, 703-705 Pacific Northwest, 288, 398, 472, 765 downbursts of air and gust fronts, 554-563 exponential, 678 past and present, as plotted on maps, 275-276 downslope windstorms, 667, 675-677 instruments to measure, 134, 321-322, 701 predictability limit, 773-775 hurricanes, 605, 626-636 logarithmic, 677, 702-703 prediction, numerical, 745-792 tornadoes, 579-580, 592-593 stable surface layer, 702-703 Richardson’s 1922 book, 764 wind waves and coastal flooding, 631-637 neutral surface layer, 677, 702 radar, 211, 240-260, 322 difference (surrogate for shear), 509 unstable radix layer, 703-705 radio, NOAA, 529, 638 magnitude, 509 profilers, 257-258, 322 reports, 267-273 vector, 509 locations worldwide, 272 station direction, 2, 314 reports of damage from, 532 ID or code (ICAO), 270 change criterion for SPECI, 270 rose, 646-647 plot model on weather maps, 274-279 constant (isogon), 18 Saffir-Simpson hurricane scale, 605-607 satellites, 112, 219-239 conversion to components, 3 scale, Beaufort, 635-636 locations of weather obs. From, 272-273 defined, 2 sensors for measuring, 321-322 sensors, 273 frequency, 646-647 arrays for airport wind shear, 556, 563 services, radars used by, 243 instruments to measure, 219 shear (also see shear), 509-522 symbols (glyphs) on weather maps, 276, 282 naming, 2, 513 components, 509 web-enhanced questions, explained, 24 radar observations of, 252-253 constant (isoshear), 18 W, X, Y, Z R. STULL • PRACTICAL METEOROLOGY 925

definition, 509, 706 atmospheric, 43, 796-797 temperature, 335 direction, 509 dirty, 220-223 flow, 330 frontal, 404-407 radiative, 43, 220-221, 796-797 breakdown, 367 in hurricane environment, 610 transmittance, 220-221 defined, 330 in thunderstorm environment, 496-499, 509- visible and IR radiometers, 45 perturbed, 367-368 522, 586-592 wing(s) propagation of baroclinic waves, 369-374 magnitude, 509 aircraft, 88 velocity from source latitudes, 361 radar observations of, 254 tip vortices, 166 wavenumber, 367 sensors at airports, 563 WINTEM code, 269 zonally averaged thermal-wind effect, causing, 345-349 winter, 330 evaporation vs. precipitation, 210 tornado formation, role in, 586-592 atmospheric boundary layer, 695-696 radiative forcings, 338-339 turbulence generation, 706, 708-709 nuclear, 151 winds at 20 kPa, 358 units, 509 solstice, 30-31, 801 zonda wind, 676 vs. stability, 141 wires, sounds from wind (aeolian noise), 560 zone, frontal, 280-281, 400-412 shield around rain gauges, 210 WMO = world meteorological organization, 149, 169, zones, time, 5 shift in fronts, 349, 400-401 268, 615 zoning for hurricanes, 631 slope, 649-653 station plot model, 275 Zulu Time, Z, defined (see UTC), 5 sounds, 560 Wolf minimum in solar activity, 803 Zworykin, Vladimir, 759 speed, 2, 3, 314 work, 54, 58, 503, 526 around highs and lows, 307 shaft, 672 constant or equal, 17 World Meteorological Organization (WMO), 149, conversion to components, 3 268 decrease across a wind turbine, 647-648 cloud classification, 168-169 defined, 3 cloud height definitions, 163 Doppler radar measurement of, 252-253 cloud symbols on weather maps, 168 for gap winds at constant depth, 661-663 hurricane and typhoon names, 615 frequency, 645-646 identification of upper-air stations, 149 instruments to measure, 219, 321-322 mandatory (upper-air) levels, 772 isotach, 17 world latitude, variation with, 359 circulations (global), 329-388 mean, 705, 726-727 climate processes (natural), 793-832 probability, 645 map of annual precipitation, 209 probability distribution - Weibull, 645-646 record rainfall rates, 208, 545-548 profile, 702-705 Wreck of the Hesperus, 847 radial speed, 249-253 WRF (weather research & forecasting) model, 751 relative frequency, 645-646 WSR-88D weather surveillance radar, 243 weather-map symbols, 278 wstar (w*, see Deardorff velocity), 69, 110, 703-704, Weibull distribution, 645-646 736 speed profile, 699-705 storm downslope, 667, 675-677 force winds (Beaufort scale), 635-636 storm-relative, 584-585 X straight-line (also see derecho), 489, 491, 494, 554, X band radar, 242 560-563 x direction definition, 2 stress, 700-713 change to match mean wind direction, 649-653, ocean currents driven by, 701 727 subgeostrophic, 304, 455, 699 xenon, Xe, 7 summary of, horizontal, 302, 313-314 x rays, 222 supergeostrophic, 304, 455, 699-700 supergradient, 643 superposition of mean, waves & gusts, 705-706 surface layer, 699-705 Y measuring height, 701 y-direction definition, 2 thermal, 345-349 year African easterly jet, 611 leap, 31 derived, 346 sidereal, 29 thunder shock front, associated, 572-574 tropical, 31 -torn clouds (fractus), 165-166 without summer, 1816, 805 tornadic, 385, 577-580 yellow color defined (also see optics chapter), 37 exploding houses, 674 Yellowstone caldera, 805 total (rotational + translational), 578, 627-628 yocto (10–24), 870 trade, 330-331 Yogi Berra (see Berra) tropopause (jet stream), 357-362 yotta (1024), 870 tunnels, boundary-layer growth in, 689 Young-Laplace equation, 215 turbines and power generation, 647-648 efficiency, 647-648 power output curve, 648 pressure change across, 671 turbulent part, 705-706 Z upper-tropospheric, global, 331-332 z direction definition, 2 upslope, 649-652 Z (radar reflectivity factor), 245-246 urban canopy, 678-679 Z time zone, defined (see UTC), 5 valley winds, 649-654, 660-670, 675-676 Z-R relationship, 247 vane, 219, 321-322 zenith variance of, 706-711, 727 angle defined, 4-5 vector weather map case study, 438, 440 circumzenith arcs, 848-849 veering, 349, 511, 520 point, 854 vertical speed zepto (10–21), 870 downburst, 554-559 zero in extratropical cyclones, 451-462 absolute, 879 in hurricanes, 628-629 buoyancy, 135, 688 in thunderstorms, 508, 557 isodop, 250, 253-254 omega, 451, 456-459 set, 171 waves on ocean, 634-636 zetta (1021), 870 weather maps, 290-291, 440 zi = mixed layer depth, 143-144 westerlies, 331-332 Zinsser, William, 863 whistling wires (aeolian tones), 560 zo = roughness length, 677-678 zonally averaged at 20 kPa, 358 zonal zonda, 676 average window heat transport, 339, 378 absorption, 43 insolation, radiation, 336-338 926 INDEX