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Ariel E. Cohen, Steven M. Cavallo, Michael C. Coniglio, and Harold E. Brooks

necessary conditions are marginally supportive of severe weather, in which small errors can be very meaningful (e.g., Vescio and Thompson 1998 ). This may be a reason why southeastern U.S. cold season severe weather has not been extensively studied, especially in regard to mesoscale modeling and related PBL schemes. Factors like shear-driven eddies and large-scale vertical motion influence the thermodynamic and kinematic properties of the PBL in this regime, in addition to heat fluxes from diurnal

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Glen S. Romine, Craig S. Schwartz, Ryan D. Torn, and Morris L. Weisman

forecast uncertainty. M11 further noted that the impact of a group of observations on a particular forecast depends on the following factors, which are carefully considered in this study: Errors that are present in the background forecast without targeted observations. Errors in the observations. The data assimilation and forecast methods employed. Over the central Great Plains, mid- to upper-tropospheric weather disturbances often modulate severe storm development. These disturbances frequently pass

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Leigh A. Baumgart, Ellen J. Bass, Brenda Philips, and Kevin Kloesel

1. Introduction a. Emergency management during severe weather The United States experiences some of the most severe thunderstorms and violent tornadoes anywhere in the world ( FEMA 2007 ). Between 1950 and 1999, tornadoes accounted for an average of 89 fatalities each year ( SPC 2007 ). On 3 May 1999 alone, 58 tornadoes occurred in Oklahoma, leaving 45 people dead and 600 injured ( Brown et al. 2002 ). One critical role that emergency managers (EMs) play is to alert the public of approaching

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John F. Weaver and Nolan J. Doesken

SEPTEMBER 1991 FORECASTER'S FORUM 411FORECASTER'S FORUMHigh Plains Severe Weather--Ten Years AfterJOHN F. WEAVERNOAA /NESDIS/RAMM Branch, Fort Collins, ColoradoNOLAN J. DOESKENColorado Climate Center, Colorado State University, Fort Co#ins, Colorado20 December 1990 and 21 February 1991ABSTRACT More than a decade ago, a study was published that identified a short list of precursor conditions for

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Chad M. Shafer, Andrew E. Mercer, Michael B. Richman, Lance M. Leslie, and Charles A. Doswell III

1. Introduction The identification of major severe weather outbreaks has been a primary objective of severe weather forecasting for decades ( Schaefer 1986 ; Johns and Doswell 1992 ; Doswell et al. 1993 ; Doswell 2007a ). As these events typically are responsible for a substantial portion of high impact severe weather observed in a given year (e.g., Doswell et al. 2006 , hereafter D06 ; Verbout et al. 2006 ; Brotzge and Erickson 2009 , 2010 ), methods that can discriminate major severe

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Aaron J. Hill, Gregory R. Herman, and Russ S. Schumacher

1. Introduction Severe weather, as defined in the United States, includes three distinct phenomena: 1) the presence of one or more tornadoes of any intensity, 2) the presence of 1 in. (2.54 cm) or larger hail, or 3) convectively induced wind gusts of at least 58 mph (93 km h −1 ). Beyond these criteria, tornadoes of F2 or EF2 strength or greater, hail 2 in. (5.08 cm) or larger in diameter, or wind gusts of at least 74 mph (119 km h −1 ), pose particularly elevated threats to life and property

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hi :Y 1963MONTHLY WEATHER REVIEW207precedes the event.1. INTRODUCTIONThe electromagnetic radiation spectrum produced bylightning and other lightning-related discharges occurringduring cumulonimbus cloud activity has been detected atlllonitor frequencies ranging from very low frequency(VLF) to microwave frequencies. An extensive attemptto relate VLF sferics data to severe weather was made bythe US. Air Force [l, 21. The results indicated that al-though no apparent correlation existed at 10 kc

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Takemasa Miyoshi, Masaru Kunii, Juan Ruiz, Guo-Yuan Lien, Shinsuke Satoh, Tomoo Ushio, Kotaro Bessho, Hiromu Seko, Hirofumi Tomita, and Yutaka Ishikawa

of big data, typically characterized by four “big V’s” (volume, variety, velocity, and veracity), are growing rapidly, and BDA is one of the first two projects awarded by the Japanese government strategic funding program started in 2013 on general big data applications. 1 In contemporary weather forecasting, radar observations and NWP play an essential role in real-time monitoring and short-term prediction of severe weather. The widely used parabolic-antenna radar observes rain intensity along a

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Richard P. McNulty

662 MONTHLY WEATHER REVIEW VoLuM~I06On Upper Tropospheric Kinematics and Severe Weather Occurrence P~cBxzo P. McNuLx-National Sere Sto. ns F~e~a~l C~, Ka~ C~y, Mo. 64106(M~u~pt ~eiv~ 1 ~tember 1977, in ~ [o~ 3 Febma~ 1978) ABSTRACT Upper tropospheric wind maxima and their associated divergence fields are examined in terms of severeweather occurrence. A two-part project is

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R. E. Smith and R. J. Hung

. Acknowledgments. The able mathematical assistanceof Dr. David A. Perry was welcomed.REFERENCESBoatman, Joey F., 1974: The effects of tropospheric temperature lapse rates on the ascent rates of pilot balloons. J. Appl. Meteor., 13, 955-961.U. S. Weather Bureau, 1942: Instructions for Making Pilot Balloon Observations. Circular O, Weather Bureau Manual No. 1278, Govt. Printing Office, Washington, D. C., 65 pp.Observation of Severe Weather Activities by Doppler Sounder Array R. E

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