NOAA Technical Memorandum NWS WR84
Total Page:16
File Type:pdf, Size:1020Kb
NOAA TM NWS WR84 NOAA Technical Memorandum NWS WR84 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Weather Service Southwestern United States Summer Monsoon Source -- Gulf of Mexico or Pacific Ocean? JOHN E. HALES, JR. Western Region SALT LAKE CITY, UTAH March 1973 .. NOAA TECI:!N ICAL MEI40RANOA National Weather Service, Western Region Subseries The National Weather Service (NWSJ Western Region (WR) Subseries provides an informal medium for the documentation and quick dissemination of results not appropriate, or not yet ready, for formal pub I !cation. The series Is used to report on work in progress, to describe technical procedures and practices, or to relate.progres~ to a I imited audience. These Technical Memoranda wil I report on investigations. devoted prlmari ly to reg1onal an~ !~cal problems· of interest mainly to personnel, and hence wi II not be widely distributed. Papers I to 23 are in the former series, ESSA Technical Memoranda, Western Region Technical Memoranda CWRTMJ; papers 24 to 59 are In the former series, ESSA Technical Memoranda, Weather Bureau Technical Memoranda (WBTMJ. Beginning with 60, the papers are part of the series, NOAA Technical Memoranda NWS. Papers I to 23, except for 5 (revised edition) and 10, are available from the National Weather Service Westecn Region, Scientific Services Division, p, 0. Box 11188, Federal Building, 125 South State Street, Salt Lake C1ty, · Utah 841 I I, Papers.5 (revised edition), 10, and alI others beginning ~ith 24 are available from t~e N~tional Technical Information Service, U.S. Department of Commerce, Si I Is Bldg., 5285 Port Royal Road, Spr1ngf1eld, Va. 22151, Price: $3.00 paper copy; $0.95 microfiche. Order by accession number shown in parentheses at end of each entry. ,. ESSA Technical Memoranda WRTM I Some Notes on Probabi! tty Forecasting. Edward D. Diemer, September 1965. (Out of print,) WRTM 2 Climatological Precipitation Probabi I !ties. Campi led by Lucianna Mi I fer, December 1965. WRTM 3 Western Region Pre- and Post-FP-3 Program, December I, 1965 to February 20, 1966. Edward D. Diemer, March 1966. WRTM 4 Use of Meteorological Sate! I !te Data. March !966. WRTM 5 Station Descriptions of Local Effects on Synoptic Weather Patterns. Philip Wil I lams, Jr., Apri I 1966 (revised November 1967, October 1969), (PB-178000) WRTM 6 Improvement of Forecast ~lording and Format. C, L. GI enn, May 1966. WRTM 7 Final Report on Precipitation Probabil tty Test Programs. Edward D. Diemer, May 1966. WRTM 8 Interpreting the RAREP. Herbert P. Benner, May 1966 (revised January 1967). (Out of print.) WRTM 9 A Collection of Papers Related to the 1966 NMC Primitive-Equation Model. June 1966. ~IRTM I 0 Sonic Boom. Loren Crow (6th Weather Wing, USAF, Pamphlet), June 1966. (Out of print.) CAD-479366) ~IRTM II Some Electrical Processes in the Atmosphere. J, Latham, June 1966. 'rlRTM !2 A Comparison-of Fog Incidence at Missoula, Montana, with Surrounding Locations. Richard A. Dightman, August 1966. (Out of print.) WRTM 13 A Collection of Technical Attachments on the 1966 NMC Primitive-Equation Model, Leonard W. Snel !man, August 1966. (Out of print.) ; WRTM 14 Appl !cation of Net Radiometer Measurements to Short-Range Fog and Stratus Forecasting at Los Angeles. Frederick Thomas, September 1966. WRTI'I 15 The Use of the Mean as an Estimate of "Normal" Precipitation in an Arid Region. Paul C. Kangieser, November 1966. ~1Rn1 16 Some Notes on Ace! imatization in Man. Edited by Leonard W. Snel !man, November 1966. WRTI•1 17 A Digitalized Summary of Radar Echoes Within 100 Miles of Sacramento, California. J, A. Youngberg and L. 8. Overaas, December 1966. WRTM 18 Limitations of Selected Meteorological Data. December !966. WRTM 19 A Grid ~~ethod for Estimating Precipitation Amounts by Using the WSR-57 Radar. R. Granger, D.ecember 1966. (Out of print. l WRTM 20 Transmitting Radar Echo Locations to Local Fire Control Agencies for Lightning Fire Detection. Robert R. Pe1·erson, March 1967, (Out of prInt,) WRTM 21 fl.n Objective Aid for Forecasting the End of East Winds in the Columbia Gorge, July through October. D. John Coparanis, April 1967. WRTM 22 Derivation of Radar Horizons in t4ountainous Terrain. Roger G. Pappas, Apri I 1967. WRTM 23 "K" Chart Appl !cations to Thunderstorm Forecasts Over the Western United States. Richard E. Hambidge, May 1967. ESSA Techn i ca I r~emoranda, Weather Bureau Techn i ca I Memoranda (;IBTMl WBm 24 Historical and Climatological Study of Grinnel I Glacier, Montana. Richard A. Dightman, July 1967. (PB-178071 l WBTM 25 Verification of Operational Probabi I ity of Precipitation Forecusts, Apri I 1966-March 1967. W. W. Dickey, October 1967. (PB-176240) WBTM 26 A S·rudy of Winds in the Lake Mead Recreation Area. R. p, Augul is, January 1968. (PB-177830) ~IBT~1 27 Objective Minimum Temperature Forecasting for Helena, Montana. D. E. Olsen, February 1968. (PB-177827) WBTM 28 •leather Extremes. R. J, Schmid!!, April 1968 (revised July 1968). (PB-178928) WBT~1 29 Sma I I -Sea I e. Ana I ys is and Prediction. Phi I i p ~li I I i ams, Jr., May 1968. ( PB-178425 J WBTtol 30 Numerical Weather Prediction and Synoptic Meteorology. Capt. Thomas D. Murphy, U.S.A.F., May 1968. (A0-673365) . 'rlBTM 31 Precipitation Detection Probabi I ities by Salt Lake ARTC Radars. Robert K. Belesky, July 1968. ( PB-1 79084 l WBTM 32 Probabi I ity Forecasting--A Problem Analysis with Reference to the Portland Fire Weather District. Harold S. Ayer, July 1968. (PB-179289) WBTM 33 Objective Forecasting. Phi I i p Wi I I i arns, J r,, August 1968, <AD-680425) \1Bn4 34 The WSR-57 Radar Program at Missoula, Montana. R. Granger, October 1968. (PB-180292) \113TM 35 Joint ESSA/FAA ARTC Radar \1eather Survei !lance Program. Herbert P. Benner and DeVon B. Smith, December 1966 (revised June 1970). (AD-681iJ57l WBTM 36 Temperature Trends in Sacramento--Another Heat Island. Anthony D. Lentini, February 1969. (Out of print.) (PB-183055) 11BTI4 37 Disposal of Logging Residues Without Damage to Air Quality. Owen P. Cramer, March 1969. CPB-183057) WBTI~ 38 Climate of Phoenix, Arizona. R. J, Schmidli, P. C. Kangieser, and R. s. Ingram. April 1969. (Out of print.) (PB-184295) WBTI·1 39 Upper-Air Lows Over Northwestern United States. A. L. Jacobson, Apri I 1969. (PB-184296) WBTM 40 The Man-t~achine 14ix in Appl led Weather Forecasting in the 1970s. L. W. Snellman, August 1969, (PB-185068) WBTI4 41 High Resolution Radiosonde Observations. W. s. Johnson, August 1969. (PB-185673) WBTI•1 42 Analysis of the Southern California Santa Ana of January 15-17, 1966. Burry B. Aronovitch, August 19(>9. (PB-185670) 'IIBTM 43 Forecasting Maximum Temperatures at Helena, Montana. David E. Olsen, October 1969. (PI3-185762) WBTM 44 Estimated Return Periods for Short-Duration Precipitation in Arizona. Paul C. Kangioser, October 1969. (PB-187763) WBTM 45/1 Precipitation Probabi I itie> in the Western Region Associated with Winter 500-mb Map Types. Richard A. Aur;u I is, December 1969, ( PB-188248) • U. S. DEPARTMENT OF COMMERCE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION NATIONAL WEATHER SERVICE NOAA Technical Memorandum NWSTM WR-84 SOUTHWESTERN UNITED STATES SUMMER MONSOON SOURCE - GULF OF MEXICO OR PACIFIC OCEAN? John E. Hales, Jr. Weather Service Forecast Office Phoenix, Arizona .... - . : -:. ·.-: .·.: ... ·. WESTERN REGION TECHNICAL iv1EMORANDUM NO. 84 SALT LAKE CITY, UTAH MARCH 1973 TABLE OF CONTENTS List of Figures iii I. Introduction II. · Mean C i rcu Iat ion Patterns 1-10 I. Upper-Level Circulation 2 2. Low-Level Circulation 2-10 I I 1. Summer Rainfal I Distribution I 0-11 IV. Conclusions 11-12 V. Acknowledgment 12 VI. References 12 .".·.· i i LIST OF FIGURES Figure I. Mean 700-mb Contours--June, July, August, and September 13 Figure 2. Average Precipitable Water Vapor, in Centimeters, for the Eleven-Year Period (1946-1956); May through October 14 Figure 3. Average August 1969 Dew Point and Temperature Soundings for Mazatlan, Mexico, and Tucson, Arizona 15 Figure 4. Mean Sea-Surface Temperature (°F.), August 16 Figure 5. Mean 850-mb Chart of Temperature (°C), Mixing Ratio Cgm/kg), Wind (mph), and Height (Meters) for Ten-Year Period (1962-1971 ), June. Ful I Wind Barb Equals 10 mph 17 Figure 6. Same Chart as Figure 5, Except for July 18 Figure 7. Same Chart as Figure 5, Except for August 19 Figure 8. Same Chart as Figure 5, Except for September 20 Figure 9. 'Mean June 1000-mb Heights (Meters) 21 Figure 10. Mean July 1000-mb Heights (Meters) 22 Figure I I. Mean August 1000-mb Heights (Meters) 23 Figure 12. Mean September 1000-mb Heights (Meters) 24 Figure 13. Five-Day Running Means of 850-mb Relative Humidity at Tucson and 850-mb Temperature (°C) at Empalme, September 1972 25 . ... ~ ' . Figure 14. Mean July-August Rainfall in Mi II imeters 26 iii SOUTHWESTERN UNITED STATES SUMMER MONSOON SOURCE - GULF OF MEXICO OR PACIFIC OCEAN? ... I. INTRODUCTION .... .. During summer the interior of the United States and northern Mexico west of the Continental Divide experience frequent intrusions of moist tropical air. In the months of July and August the greatest northward flux occurs. June and September are transition months from spring to summer and summer to fal I, respectively. During these months, particularly June, there is a predominance of rather dry air-mass conditions. In July and August the air mass is normally quite moist from north western Mexico southward. The frequency of moist air intrusions and their moisture content decrease nbrthward from Mexico. Arizona normally is dominated by a deep, moist air mass from the middle of July through August.