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Chauncy J. Schultz and Mark A. Askelson

nontornadic near-storm environments (NSEs) in studies such as that by Thompson et al. (2003 , hereafter T03 ). The importance of boundary layer characteristics may be related to the role of the rear-flank downdraft (RFD; Lemon and Doswell 1979 ) in tornadogenesis. Markowski et al. (2002 , hereafter M02 ) found that surface RFD air in cases of significant (F2 and greater intensity 2 ) supercellular tornadoes tended to have greater potential buoyancy compared to surface RFD air associated with

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Abdullah Kahraman, Mikdat Kadioglu, and Paul M. Markowski

1. Introduction Skillful forecasting of convective storms and their attendant hazards, such as tornadoes or large hail, requires knowledge of the characteristics of the environments in which the phenomena tend to occur. Existing studies of environmental conditions supportive of severe convective storms cover mainly the United States and parts of Europe. Rasmussen and Blanchard (1998) analyzed National Weather Service soundings from 1992 and focused on discriminating between environments

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Anthony W. Lyza, Todd A. Murphy, Barrett T. Goudeau, Preston T. Pangle, Kevin R. Knupp, and Ryan A. Wade

plateaus until reaching a maximum along the downslope gradient on the northwestern edge of Sand Mountain, in the short-axis direction of the terrain (perpendicular to the major axis of the plateaus). With the major axis of the SCS oriented approximately from 218° to 38°, such an acceleration would lead to stronger and more backed low-level flow across the SCS given southerly low-level flow in a severe storm environment, potentially increasing the magnitude of storm-relative helicity (SRH; Davies

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Adam L. Houston and Robert B. Wilhelmson

1. Introduction The central Texas storm complex of 27 May 1997 warrants examination in part simply because of its severity: the complex produced at least 12 tornadoes including three rated F3, one rated F4, and one rated F5 (the Jarrell, Texas, tornado; NCDC 1997 ). However, several specific questions have also emerged from this case. One series of questions deals with the relationship of this environment to typical tornadic supercell environments. It will be shown that the

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Alexandra K. Anderson-Frey, Yvette P. Richardson, Andrew R. Dean, Richard L. Thompson, and Bryan T. Smith

1. Introduction Our understanding of tornadoes, the morphology of their parent storms, and the characteristics of the associated near-storm environment has increased dramatically over the past few decades, as a result of both research into the physical processes governing tornadoes (e.g., Markowski and Richardson 2014 ; Davies-Jones 2015 ) and climatological studies of the environments in which tornadoes occur (e.g., Thompson et al. 2003 , 2012 ). Through conferences, publications, and

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Funing Li, Daniel R. Chavas, Kevin A. Reed, and Daniel T. Dawson II

1. Introduction Severe local storm (SLS) environments are favorable atmospheric conditions for the development of SLS events, including severe thunderstorms accompanied by damaging winds, large hailstones, and/or tornadoes ( Ludlam 1963 ; Johns and Doswell 1992 ). Such environments are commonly defined by high values of a small number of key thermodynamic and kinematic parameters: convective available potential energy (CAPE), lower-tropospheric (0–6-km) bulk vertical wind shear (S06), and 0

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Shingo Shimizu, Hiroshi Uyeda, Qoosaku Moteki, Takeshi Maesaka, Yoshimasa Takaya, Kenji Akaeda, Teruyuki Kato, and Masanori Yoshizaki

Plains because the midlevel air below the melting layer over the Great Plains is usually dry ( Carlson et al. 1983 ). Therefore, the observation and numerical study of supercells in a moist environment below the melting layer, such as that found in Japan, are important in order to investigate the effect of humidity on the formation of supercells and understand their general features. Supercells have been generally defined as storms with significantly persistent spatial collocation between updraft

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Jari-Petteri Tuovinen, Jenni Rauhala, and David M. Schultz

severe-hail environment and convective mode of storms generally do not exist. The only related studies are by Roine (2001) , who studied stability indices in thunderstorm environments in southern Finland during May–August for two years (1998 and 2000) and by Punkka and Bister (2015) , who studied the synoptic and thermodynamic environment of MCSs in Finland covering eight warm seasons (April–September for 2000–07). In contrast to Finland, many more studies have been performed on severe- or

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Matthew D. Flournoy, Michael C. Coniglio, Erik N. Rasmussen, Jason C. Furtado, and Brice E. Coffer

understood, at least at midlevels. 3 Horizontal vorticity in the near-storm environment is tilted into the vertical and stretched by a convective updraft ( Rotunno 1981 ; Lilly 1982 ; Davies-Jones 1984 ; Dahl 2017 ). The spatial correlation between vertical velocity and vorticity increases as the angle between the environmental horizontal vorticity vector and wind vectors decreases (i.e., as the streamwise horizontal vorticity component increases; Davies-Jones 1984 ). Forecasters use storm

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Alexandra K. Anderson-Frey, Yvette P. Richardson, Andrew R. Dean, Richard L. Thompson, and Bryan T. Smith

provide a novel look at how outbreak and isolated tornado near-storm environments differ by geographical region within the United States. By making use of a large, comprehensive set of tornado events across the continental United States, and by establishing a definition of outbreak and isolated tornadoes consistent with our goal of comparing the near-storm environments in which both types of tornadoes generally occur, we seek to apply an established statistical toolkit (cf. Anderson-Frey et al. 2016

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