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1. Introduction It has long been recognized that the characteristics of convective storms are strongly governed by the vertical structure of the atmosphere in their immediate environment. Much of our understanding of the relationship between the near-storm environment (NSE) and the occurrence of severe convective weather (tornadoes, large hail, and damaging straight-line winds) stems from the study of proximity soundings, which dates back to the mid-twentieth century ( Showalter and Fulks 1943
1. Introduction It has long been recognized that the characteristics of convective storms are strongly governed by the vertical structure of the atmosphere in their immediate environment. Much of our understanding of the relationship between the near-storm environment (NSE) and the occurrence of severe convective weather (tornadoes, large hail, and damaging straight-line winds) stems from the study of proximity soundings, which dates back to the mid-twentieth century ( Showalter and Fulks 1943
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
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
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
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
in southern Brazil, caused in excess of the equivalent to $9.1 million (USD) in damage to crops ( EMATER/ASCAR 2021 ). Despite this potential for impacts, the environments that favor the development of severe storms based on the prevailing atmospheric ingredients (hereafter severe storm environments) are poorly understood in this region owing to a lack of reliable severe weather reports. Two primary ingredients include the presence of conditional instability and moderate to intense vertical shear
in southern Brazil, caused in excess of the equivalent to $9.1 million (USD) in damage to crops ( EMATER/ASCAR 2021 ). Despite this potential for impacts, the environments that favor the development of severe storms based on the prevailing atmospheric ingredients (hereafter severe storm environments) are poorly understood in this region owing to a lack of reliable severe weather reports. Two primary ingredients include the presence of conditional instability and moderate to intense vertical shear
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
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
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
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
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
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
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
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
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
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
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
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
