CALIFORNIA STATE UNIVERSITY, NORTHRIDGE FORECASTING CALIFORNIA THUNDERSTORMS a Thesis Submitted in Partial Fulfillment of the Re
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Soaring Weather
Chapter 16 SOARING WEATHER While horse racing may be the "Sport of Kings," of the craft depends on the weather and the skill soaring may be considered the "King of Sports." of the pilot. Forward thrust comes from gliding Soaring bears the relationship to flying that sailing downward relative to the air the same as thrust bears to power boating. Soaring has made notable is developed in a power-off glide by a conven contributions to meteorology. For example, soar tional aircraft. Therefore, to gain or maintain ing pilots have probed thunderstorms and moun altitude, the soaring pilot must rely on upward tain waves with findings that have made flying motion of the air. safer for all pilots. However, soaring is primarily To a sailplane pilot, "lift" means the rate of recreational. climb he can achieve in an up-current, while "sink" A sailplane must have auxiliary power to be denotes his rate of descent in a downdraft or in come airborne such as a winch, a ground tow, or neutral air. "Zero sink" means that upward cur a tow by a powered aircraft. Once the sailcraft is rents are just strong enough to enable him to hold airborne and the tow cable released, performance altitude but not to climb. Sailplanes are highly 171 r efficient machines; a sink rate of a mere 2 feet per second. There is no point in trying to soar until second provides an airspeed of about 40 knots, and weather conditions favor vertical speeds greater a sink rate of 6 feet per second gives an airspeed than the minimum sink rate of the aircraft. -
Winter 2020/2021 Volume 18
NATIONAL WEATHER SERVICE GREEN BAY Winter 2020/2021 Volume 18 Lake Michigan water levels remain near record highs BY: mike cellitti Inside this issue: In December 2012 and January 2013, the Lake Michigan-Huron basin (Lake Michigan and Lake Huron are treated as one lake from a hydrologic perspective) East River Watershed 3 Resiliency Project observed record low water levels, making it the 14th consecutive year of below normal water levels. These record low water levels garnered national attention 2020-21 Winter Forecast 4 raising concerns for the shipping industry, climate impacts, and the long-term future Ambassador of Excellence 6 of the Great Lakes water levels. Since this minimum in water levels 6 years ago, Lake Kotenberg Joins NWS 7 Michigan-Huron has been on the rise, culminating in record high water levels for much of this year (Figure 1). In fact, Lake Michigan-Huron set monthly mean record Severe Weather Spotters 7 high water levels from January to August, peaking in July at greater than 3 inches Thank You Observers! 8 above the previous record. Word Search 9 The water level on the Great Lakes can fluctuate on a monthly, seasonal, and annual basis depending upon a variety of factors including the amount of precipitation, evaporation, and rainfall induced runoff. Precipitation and runoff typically peak in late spring and summer as a result of snowmelt and thunderstorm activity. Although it is difficult to measure, evaporation occurs the most when cold air flows over the relatively warm waters of the Great Lakes during the fall and winter months. East River The record high water levels of Lake Michigan-Huron are largely a result of well Flooding above normal precipitation across the basin over the past 5 years. -
USING a LIGHTNING SAFETY TOOLKIT for OUTDOOR VENUES Charles C
USING A LIGHTNING SAFETY TOOLKIT FOR OUTDOOR VENUES Charles C. Woodrum Meteorologist National Weather Service, NOAA Pittsburgh, Pennsylvania Donna Franklin Office of Climate, Water, and Weather Services National Weather Service, NOAA Silver Spring, Maryland _________________________ Abstract guidelines that are used as a template for creating a new plan or enhancing an existing plan. The toolkit The threat of fatal lightning strikes at outdoor was developed within the framework of NCAA venues continues to be a pressing concern for event Guideline 1d. The NWS used plans from the managers. Several delays were documented in 2010 University of Tampa, the University of Maryland, and and 2011 in which spectators did not have enough time Vanderbilt University along with guidance from to evacuate, or chose to wait out delays in unsafe emergency management at the University of locations. To address this issue, the National Weather Tennessee and Florida State University as assistance Service (NWS) developed a lightning safety toolkit and to develop the toolkit. recognition program to help meteorologists work with venue officials to encourage sound and proactive Guidelines established for venue decisions when thunderstorms threaten their venue. management include: redundant data reception sources; effective decision support standards; 1. Introduction and Background multiple effective communication methods; a public notification plan; protection program with shelters; and Every year, hundreds of outdoor venue education of staff and patrons. The toolkit template managers are challenged to determine when an event safety plan helps venues meet these guidelines by delay is necessary due to thunderstorm hazards. In providing steps to follow before, during, and after the 2000, “ninety-two percent of National Collegiate Athletic event. -
Climatology, Variability, and Return Periods of Tropical Cyclone Strikes in the Northeastern and Central Pacific Ab Sins Nicholas S
Louisiana State University LSU Digital Commons LSU Master's Theses Graduate School March 2019 Climatology, Variability, and Return Periods of Tropical Cyclone Strikes in the Northeastern and Central Pacific aB sins Nicholas S. Grondin Louisiana State University, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_theses Part of the Climate Commons, Meteorology Commons, and the Physical and Environmental Geography Commons Recommended Citation Grondin, Nicholas S., "Climatology, Variability, and Return Periods of Tropical Cyclone Strikes in the Northeastern and Central Pacific asinB s" (2019). LSU Master's Theses. 4864. https://digitalcommons.lsu.edu/gradschool_theses/4864 This Thesis is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Master's Theses by an authorized graduate school editor of LSU Digital Commons. For more information, please contact [email protected]. CLIMATOLOGY, VARIABILITY, AND RETURN PERIODS OF TROPICAL CYCLONE STRIKES IN THE NORTHEASTERN AND CENTRAL PACIFIC BASINS A Thesis Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Master of Science in The Department of Geography and Anthropology by Nicholas S. Grondin B.S. Meteorology, University of South Alabama, 2016 May 2019 Dedication This thesis is dedicated to my family, especially mom, Mim and Pop, for their love and encouragement every step of the way. This thesis is dedicated to my friends and fraternity brothers, especially Dillon, Sarah, Clay, and Courtney, for their friendship and support. This thesis is dedicated to all of my teachers and college professors, especially Mrs. -
The Iberian Peninsula Thermal Low
Q. J. R. Meteorol. Soc. (2003), 129, pp. 1491–1511 doi: 10.1256/qj.01.189 The Iberian Peninsula thermal low 1 2 By KLAUS P. HOINKA ¤ and MANUEL DE CASTRO 1Institut fur¨ Physik der Atmosph¨are, DLR, Oberpfaffenhofen, Germany 2Dpto. Ciencias Ambientales, Universidad Castilla-La Mancha, Toledo, Spain (Received 9 November 2001; revised 26 September 2002) SUMMARY Statistics of the thermal low above the Iberian Peninsula are presented for the period between 1979 and 1993, based on gridded data from the European Centre for Medium-Range Weather Forecasts reanalysis project. The sample of days with a thermal low above the Iberian Peninsula was selected objectively using criteria applied to mean-sea-level pressure and 925 hPa geopotential elds. The synoptic- and regional-scale horizontal structure is characterized by the climatology of the 500 hPa geopotential and mean-sea-level pressure distributions. The diurnal evolution of the mean-sea-level pressure is portrayed by mean elds at 00, 06, 12 and 18 UTC. The climatological vertical structure of the thermal low is shown by relation to meridional and zonal cross- sections passing through the thermal low’s centre. The diurnal evolution of the divergence, relative vorticity, potential temperature and vertical velocity is investigated. Statistics are presented also for the monthly frequency, geographical location, vertical extent and intensity of the Iberian thermal low. KEYWORDS: ERA data Heated low 1. INTRODUCTION A thermal low is a warm, shallow, non-frontal depression which forms above continental regions, mostly in the subtropics, but also in the lower midlatitudes. They form mostly during summer months because of the intense surface heating over land. -
MSE3 Ch14 Thunderstorms
Chapter 14 Copyright © 2011, 2015 by Roland Stull. Meteorology for Scientists and Engineers, 3rd Ed. thunderstorms Contents Thunderstorms are among the most violent and difficult-to-predict weath- Thunderstorm Characteristics 481 er elements. Yet, thunderstorms can be Appearance 482 14 studied. They can be probed with radar and air- Clouds Associated with Thunderstorms 482 craft, and simulated in a laboratory or by computer. Cells & Evolution 484 They form in the air, and must obey the laws of fluid Thunderstorm Types & Organization 486 mechanics and thermodynamics. Basic Storms 486 Thunderstorms are also beautiful and majestic. Mesoscale Convective Systems 488 Supercell Thunderstorms 492 In thunderstorms, aesthetics and science merge, making them fascinating to study and chase. Thunderstorm Formation 496 Convective Conditions 496 Thunderstorm characteristics, formation, and Key Altitudes 496 forecasting are covered in this chapter. The next chapter covers thunderstorm hazards including High Humidity in the ABL 499 hail, gust fronts, lightning, and tornadoes. Instability, CAPE & Updrafts 503 CAPE 503 Updraft Velocity 508 Wind Shear in the Environment 509 Hodograph Basics 510 thunderstorm CharaCteristiCs Using Hodographs 514 Shear Across a Single Layer 514 Thunderstorms are convective clouds Mean Wind Shear Vector 514 with large vertical extent, often with tops near the Total Shear Magnitude 515 tropopause and bases near the top of the boundary Mean Environmental Wind (Normal Storm Mo- layer. Their official name is cumulonimbus (see tion) 516 the Clouds Chapter), for which the abbreviation is Supercell Storm Motion 518 Bulk Richardson Number 521 Cb. On weather maps the symbol represents thunderstorms, with a dot •, asterisk , or triangle Triggering vs. Convective Inhibition 522 * ∆ drawn just above the top of the symbol to indicate Convective Inhibition (CIN) 523 Trigger Mechanisms 525 rain, snow, or hail, respectively. -
Tropical Cyclone Effects on California
/ i' NOAA Technical Memorandum NWS WR-~ 1s-? TROPICAL CYCLONE EFFECTS ON CALIFORNIA Salt Lake City, Utah October 1980 u.s. DEPARTMENT OF I National Oceanic and National Weather COMMERCE Atmospheric Administration I Service NOAA TECHNICAL ME~RANOA National Weather Service, Western R@(Jfon Suhseries The National Weather Service (NWS~ Western Rl!qion (WR) Sub5eries provide! an informal medium for the documentation and nUlck disseminuion of l"'eSUlts not appr-opriate. or nnt yet readY. for formal publication. The series is used to report an work in pronf"'!ss. to rie-tJ:cribe tl!1:hnical procedures and oractice'S, or to relate proqre5 s to a Hmitfd audience. The~J:e Technical ~ranc1i!l will report on investiqations rit'vot~ or'imaroi ly to rl!nionaJ and local orablems of interest mainly to personnel, "'"d • f,. nence wUl not hi! 'l!lidely distributed. Pacer<; I to Z5 are in the fanner series, ESSA Technical Hetooranda, Western Reqion Technical ~-··•nda (WRTMI· naoors 24 tn 59 are i·n the fanner series, ESSA Technical ~-rando, W.othel" Bureou Technical ~-randa (WSTMI. aeqinniM with "n. the oaoers are oa"t of the series. ltOAA Technical >4emoranda NWS. Out·of·print .....,rond1 are not listed. PanfiM ( tn 22, except for 5 {revised erlitinn), ar'l! availabll! froM tt'lt Nationm1 Weattuu• Service Wesurn Ret1inn. )cientific ~•,.,irr• Division, P.O. Box lllAA, Federal RuildiM, 125 South State Street, Salt La~• City, Utah R4147. Pacer 5 (revised •rlitinnl. and all nthei"S beqinninq ~ith 25 are available from the National rechnical Information Sel'"lice. II.S. -
1858 San Diego Hurricane and Not Be Sur- Documented to Be Real
THE SAN DIEGO HURRICANE OF 2 OCTOBER 1858 BY MICHAEL CHENOWETH AND CHRISTOPHER LANDSEA The discovery of a hurricane that directly impacted San Diego, California, nearly 150 yr ago has implications for residents and risk managers in their planning for extreme events for the region. ropical cyclones forming in the eastern North 10 September 1976 in California and Arizona, and Pacific Ocean are occasional visitors to the Hurricane Nora in September 1997 in Arizona. Only T southwestern United States. By the time these the 1939 tropical storm made a direct landfall in coastal systems travel far enough to the north to bring their California (Smith 1986), because the other three sys- associated moisture to the United States, the tropical tems entered the United States after first making land- cyclones have normally diminished below tropical fall in Mexico. storm strength over Mexico or over the colder waters The 1939 tropical storm caused $2 million in prop- of the California Current that flows southward along erty damage in California, mostly to shipping, shore the California coast. Rain, sometimes locally excessive, structures, power and communication lines, and crops. is frequently observed in many areas of the southwest- Ships in coastal waters of southern California reported ern United States when tropical cyclone remnants en- southeast winds between 34 and 47 kt (Hurd 1939). ter the region (Blake 1935; Smith 1986). However, no tropical cyclones are recorded or esti- Four tropical cyclones have managed to bring tropi- mated to have made landfall in the southwestern cal storm–force winds to the southwestern United United States as a hurricane, with maximum 1-min States during the twentieth century: a tropical storm surface (10 m) winds of at least 64 kt. -
Dynamical and Synoptic Characteristics of Heavy Rainfall Episodes in Southern Brazil
598 MONTHLY WEATHER REVIEW VOLUME 135 Dynamical and Synoptic Characteristics of Heavy Rainfall Episodes in Southern Brazil MATEUS DA SILVA TEIXEIRA Instituto Nacional de Pesquisas Espaciais, Sdo Jose dos Campos, Sdo Paulo, Brazil PRAKKI SATYAMURTY Centro de Previsao de Tempo e Estudos Climdticos/INPE,Sio Jose dos Campos, Sdo Paulo, Brazil (Manuscript received 21 December 2005, in final form 19 May 2006) ABSTRACT The dynamical and synoptic characteristics that distinguish heavy rainfall episodes from nonheavy rainfall episodes in southern Brazil are discussed. A heavy rainfall episode is defined here as one in which the 2 50 mm day-' isohyet encloses an area of not less than [0 000 km in the domain of southern Brazil. One hundred and seventy such events are identified in the 11-yr period'of 1991-2001. The mean flow patterns in the period of 1-3 days preceding the episodes show some striking synoptic-scale features that may be considered forerunners of these episodes: (i) a deepening midtropospheric trough in the eastern South Pacific approaches the continent 3 days before, (ii) a surface low,pressure center forms in northern Ar- gentina 1 day before, (iii) a northerly low-level jet develops over Paraguay 2 days before, and (iv) a strong moisture flux convergence over southern Brazil becomes prominent 1 day before the episode. A parameter called rainfall quantity, defined as the product .of the area enclosed by the 50 mm day-' isohyet and the average rainfall intensity, is,correlated with fields of atmospheric variables such as 500-hPa geopotential and 850-hPa meridional winds. Significant lag correlations show that the anomalies of some atmospheric vari- ables could be viewed as precursors of heavy rainfall in southern Brazil that can be explored for use in improving the forecasts. -
The Use of Hyperspectral Sounding Information to Monitor Atmospheric Tendencies Leading to Severe Local Storms
PUBLICATIONS Earth and Space Science RESEARCH ARTICLE The use of hyperspectral sounding information 10.1002/2015EA000122-T to monitor atmospheric tendencies leading Key Points: to severe local storms • Hyperspectral sounders add independent information to Elisabeth Weisz1, Nadia Smith1, and William L. Smith Sr.1 existing data sources • Time series of retrievals provides 1Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA valuable details to storm analysis • Forecasters are encouraged to utilize hyperspectral data Abstract Operational space-based hyperspectral sounders like the Atmospheric Infrared Sounder, the Infrared Atmospheric Sounding Interferometer, and the Cross-track Infrared Sounder on polar-orbiting satellites provide radiance measurements from which profiles of atmospheric temperature and moisture can Correspondence to: be retrieved. These retrieval products are provided on a global scale with the spatial and temporal resolution E. Weisz, [email protected] needed to complement traditional profile data sources like radiosondes and model fields. The goal of this paper is to demonstrate how existing efforts in real-time weather and environmental monitoring can benefit from this new generation of satellite hyperspectral data products. We investigate how retrievals from all four Citation: Weisz, E., N. Smith, and W. L. Smith Sr. operational sounders can be used in time series to monitor the preconvective environment leading up to the (2015), The use of hyperspectral sounding outbreak of a severe local storm. Our results suggest thepotentialbenefit of independent, consistent, and information to monitor atmospheric fi tendencies leading to severe local high-quality hyperspectral pro le information to real-time monitoring applications. storms, Earth and Space Science, 2, doi:10.1002/2015EA000122-T. -
The San Diego Hurricane of 2 October 1858
THE SAN DIEGO HURRICANE OF 2 OCTOBER 1858 BY MICHAEL CHENOWETH AND CHRISTOPHER LANDSEA The discovery of a hurricane that directly impacted San Diego, California, nearly 150 yr ago has implications for residents and risk managers in their planning for extreme events for the region. ropical cyclones forming in the eastern North 10 September 1976 in California and Arizona, and Pacific Ocean are occasional visitors to the Hurricane Nora in September 1997 in Arizona. Only Tsouthwestern United States. By the time these the 1939 tropical storm made a direct landfall in coastal systems travel far enough to the north to bring their California (Smith 1986), because the other three sys- associated moisture to the United States, the tropical tems entered the United States after first making land- cyclones have normally diminished below tropical fall in Mexico. storm strength over Mexico or over the colder waters The 1939 tropical storm caused $2 million in prop- of the California Current that flows southward along erty damage in California, mostly to shipping, shore the California coast. Rain, sometimes locally excessive, structures, power and communication lines, and crops. is frequently observed in many areas of the southwest- Ships in coastal waters of southern California reported ern United States when tropical cyclone remnants en- southeast winds between 34 and 47 kt (Hurd 1939). ter the region (Blake 1935; Smith 1986). However, no tropical cyclones are recorded or esti- Four tropical cyclones have managed to bring tropi- mated to have made landfall in the southwestern cal storm-force winds to the southwestern United United States as a hurricane, with maximum 1-min States during the twentieth century: a tropical storm surface (10 m) winds of at least 64 kt. -
WOIS - Meteorologists
WOIS - Meteorologists http://www.wois.org/use/occs/viewer.cfm?occnum=100014 University of Washington Libraries Meteorologists Occupational Summary At a Glance Meteorologists study the earth's atmosphere and the ways it affects our environment. Many of them forecast Not all forecast the the weather. weather Many specialize in Have you ever wondered why hurricanes receive names? The reason is actually quite simple: there is often one area more than one at a time. Hurricanes can also take days to travel over the ocean, gaining or losing strength. By May work overtime naming them, meteorologists can track them without confusion. They don't waste time coming up with new during weather names, however. Instead, meteorologists use a list of pre-selected names. Only when a storm is particularly big emergencies do they retire a name. Thus, there will never be another Hurricane Andrew or Hurricane Fifi, although there Have good research may be more hurricanes just as powerful. and communication The atmosphere consists of all the air that covers the earth. It also contains the water vapor that turns into rain skills and snow. Meteorologists study what the atmosphere is made of and how it works. They also see how it affects Have at least a the rest of our environment. bachelor's degree Meteorologists usually specialize in one area. Weather forecasting is the best known of these. Meteorologists who forecast the weather are called operational meteorologists. They identify and interpret weather patterns to predict the weather. They try to predict what the weather will be like for a week, a month, or several years.