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Steven V. Vasiloff
and
Kenneth W. Howard

1. Introduction During the past 10 yr, the frequency of damaging winds from downbursts occurring in the Phoenix, Arizona, metropolitan area and surrounding suburbs has markedly increased, presumably due to population growth and better reporting ( SPC 2007 ). Within the southwestern U.S. Sonoran Desert, downbursts from severe storms frequently produce strong outflows that entrain dust and reduce visibility to dangerous levels, particularly hazardous to traffic along the Interstate Highway System

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Katherine L. Horgan
,
David M. Schultz
,
John E. Hales Jr.
,
Stephen F. Corfidi
, and
Robert H. Johns

by Rochette and Moore (1996) , Rochette et al. (1999) , and Moore et al. (1998 , 2003 ) focused on elevated convective storms that produce heavy rainfall, finding they were associated with elevated instability. Sometimes elevated convection produces severe weather in the form of large hail, strong winds, and/or tornadoes (e.g., Branick et al. 1988 ; Colman 1990b ; Schmidt and Cotton 1989 ; Bernardet and Cotton 1998 ; Banacos and Schultz 2005 ). Grant (1995) examined 11 cases of

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Harold E. Brooks
,
Charles A. Doswell III
,
Xiaoling Zhang
,
A. M. Alexander Chernokulsky
,
Eigo Tochimoto
,
Barry Hanstrum
,
Ernani de Lima Nascimento
,
David M. L. Sills
,
Bogdan Antonescu
, and
Brad Barrett

1. Introduction There are many variations in the definition of what constitutes a severe convective storm. From a physical perspective, a convective storm is one driven by buoyancy. Buoyancy is determined by differences in air density leading to a vertical pressure gradient that is unbalanced by gravity, leading in turn to the development of vertical acceleration ( Doswell and Markowski 2004 ). Note that buoyancy can be either negative or positive, so the vertical acceleration due to buoyancy

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Ruoyun Ma
,
Jianhua Sun
, and
Xinlin Yang

1. Introduction Severe convective weather (SCW), such as short-duration heavy rainfall (SDHR), thunderstorm high winds (THWs), and hail, occurs frequently over North China ( J. Chen et al. 2013a ; Yang et al. 2017 ; Li et al. 2018 ) and poses a great threat to life and property in this region. Accurate forecasting of severe convective storms (SCSs) over North China is particularly challenging, as storm initiation and evolution over this region are influenced greatly by the complex underlying

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Montgomery L. Flora
,
Corey K. Potvin
,
Patrick S. Skinner
,
Shawn Handler
, and
Amy McGovern

1. Introduction The National Oceanic and Atmospheric Administration (NOAA) Warn-on-Forecast program [WoF; Stensrud et al. 2009 , 2013 ] is tasked with providing forecasters with reliable, probabilistic severe weather hazard guidance at very short lead times 1 (e.g., 0–3 h). Though operational convection-allowing models (CAMs) cannot fully resolve convective processes ( Bryan et al. 2003 ), CAMs with ≤3-km horizontal grid spacing can partially resolve important storm-scale features ( Potvin

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Robert H. Johns
and
Charles A. Doswell III

588 WEATHER AND FORECASTING VOLUME7Severe Local Storms Forecastlng* ROBERT H. JOHNSNational Severe Storms Forecast Center, Kansas City, Missouri CHARLES A. DOSWELL IllNational Severe Storms Laboratory, Norman, Oklahoma(Manuscript received l 1 May 1992, in final form 13 August 1992)ABSTRACT Knowledge of severe local storms has been increasing rapidly in recent years

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Howard B. Bluestein
and
Jeffrey C. Snyder

1. Introduction Forecasting severe local storms and especially the type, location, and time of severe weather events associated with them is still a challenge, despite many years of progress in numerical weather prediction and in detection technology (e.g., Lilly 1990 ; Johns and Doswell 1992 ; Droegemeier 1997 ; Trapp et al. 2005 ; Weisman et al. 2008 ; Clark et al. 2010 ; Coniglio et al. 2010 ; Kain et al. 2013 ). Major challenges include defining the large-scale forcing and

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Pamela L. Heinselman
,
David L. Priegnitz
,
Kevin L. Manross
,
Travis M. Smith
, and
Richard W. Adams

aircraft surveillance, in light of the associated technological, operational, and cost issues, is given by Weber et al. (2007) . Advantages of PAR for weather monitoring and improving data quality are examined by Zrnić et al. (2007) . This paper is the first detailed investigation of the capability of PAR, developed by the military for aircraft and missile surveillance, to provide high temporal resolution weather surveillance of severe storms. For comparison to conventional radars, this study

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Brenda C. Johnson
,
Judith Stokes
, and
Peter S. Ray

-frequency data. Misc Pub. U. S. Dept. Agric., No. 204, Washington, DC, 68 ppVelocity Distributions'within Oklahoma Severe StormsBRENDA C. JOHNSON, JUDITH STOKES AND PETER S. RAYNational Severe Storms Laboratory, Norman, OK 7306926 January 1979 and 18 April 1979ABSTRACT Optimum design of a Doppler radar system for operation in a severe storm environment will depend on themaximum unambiguous velocity. Radial velocities of severe storms are examined from four Doppler radarsover several hours on 20 May 1977

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Kristin M. Kuhlman
,
Conrad L. Ziegler
,
Edward R. Mansell
,
Donald R. MacGorman
, and
Jerry M. Straka

1. Introduction The Severe Thunderstorm Electrification and Precipitation Study (STEPS) took place during 2000 to study severe storms in the high plains of the United States. One of the main goals of the project was to achieve a better understanding of the interactions among storm kinematics, microphysics, and electrification, especially in storms that produce predominately positive cloud-to-ground (CG) lightning ( Lang et al. 2004 ). Numerous storms—including supercells, short-lived multicell

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