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lower tropospheric jet streaks and implications for the development of severe convective storms . Mon. Wea. Rev. , 107 , 682 – 703 , https://doi.org/10.1175/1520-0493(1979)107<0682:TCOUAL>2.0.CO;2 . Van Den Broeke , M. S. , 2021 : Polarimetric radar characteristics of tornadogenesis failure in supercell thunderstorms . Atmosphere , 12 , 581 , https://doi.org/10.3390/atmos12050581 . Van Den Broeke , M. S. , 2015 : Polarimetric tornadic debris signature variability and debris fallout
lower tropospheric jet streaks and implications for the development of severe convective storms . Mon. Wea. Rev. , 107 , 682 – 703 , https://doi.org/10.1175/1520-0493(1979)107<0682:TCOUAL>2.0.CO;2 . Van Den Broeke , M. S. , 2021 : Polarimetric radar characteristics of tornadogenesis failure in supercell thunderstorms . Atmosphere , 12 , 581 , https://doi.org/10.3390/atmos12050581 . Van Den Broeke , M. S. , 2015 : Polarimetric tornadic debris signature variability and debris fallout
Abstract
The dryline is among the most important meteorological phenomena in the Great Plains because of its significance in tornadogenesis, severe weather, and consistent rainfall. Past research has extensively examined the dynamics of the dryline; however, recent meteorological research looks beyond dynamics and focuses on land–atmosphere interactions. This study focuses on how soil moisture, a surrogate for evapotranspiration, affects the climatological longitudinal positioning of the dryline, presenting a climatological study for the months of April–June during 2006–15 in the southern Great Plains. Here, drylines are defined as specific humidity gradients exceeding 3 g kg−1 (100 km)−1 that do not deviate more than 30° from a north–south orientation; they were found to occur on 33.4% of spring days, and the most favorable position was −100.9° at 0000 UTC. Specific humidity gradients ranged from 3.0 to 15.2 g kg−1 (100 km)−1, with an average value of 6.8 g kg−1 (100 km)−1. A relationship between the dryline longitudinal position and soil moisture was found; as soil moisture values increased, the dryline was located farther west, which suggests soil moisture may influence the longitudinal positioning of the dryline. There was also a relationship between the gradient of soil moisture and the intensity (specific humidity gradient) of the dryline, such that when longitudinal soil moisture gradients were strong (increasing from west to east), the dryline intensity increased.
Abstract
The dryline is among the most important meteorological phenomena in the Great Plains because of its significance in tornadogenesis, severe weather, and consistent rainfall. Past research has extensively examined the dynamics of the dryline; however, recent meteorological research looks beyond dynamics and focuses on land–atmosphere interactions. This study focuses on how soil moisture, a surrogate for evapotranspiration, affects the climatological longitudinal positioning of the dryline, presenting a climatological study for the months of April–June during 2006–15 in the southern Great Plains. Here, drylines are defined as specific humidity gradients exceeding 3 g kg−1 (100 km)−1 that do not deviate more than 30° from a north–south orientation; they were found to occur on 33.4% of spring days, and the most favorable position was −100.9° at 0000 UTC. Specific humidity gradients ranged from 3.0 to 15.2 g kg−1 (100 km)−1, with an average value of 6.8 g kg−1 (100 km)−1. A relationship between the dryline longitudinal position and soil moisture was found; as soil moisture values increased, the dryline was located farther west, which suggests soil moisture may influence the longitudinal positioning of the dryline. There was also a relationship between the gradient of soil moisture and the intensity (specific humidity gradient) of the dryline, such that when longitudinal soil moisture gradients were strong (increasing from west to east), the dryline intensity increased.
1. Introduction During the past 20 years there have been major advances in understanding the dynamics of supercell thunderstorms and their role in tornadogenesis (see Doswell and Burgess 1993 ). Supercell storms have often been dismissed as heavy rainfall producers based on arguments revolving around low precipitation efficiency and rapid storm motion. Cotton and Anthes 1989 , for example, note that “storms producing the largest hailstones occur in strongly sheared environments; thus, in
1. Introduction During the past 20 years there have been major advances in understanding the dynamics of supercell thunderstorms and their role in tornadogenesis (see Doswell and Burgess 1993 ). Supercell storms have often been dismissed as heavy rainfall producers based on arguments revolving around low precipitation efficiency and rapid storm motion. Cotton and Anthes 1989 , for example, note that “storms producing the largest hailstones occur in strongly sheared environments; thus, in
occurrence during low snow years, are likely to cater to environments that support and maintain intense, low-level rotational centers, thereby increasing the likelihood of supercell tornadogenesis. Another effect of warming the 700-mb level, given identical surface conditions, is to reduce the depth of the afternoon mixed layer. An implied increase in potential temperature jump across the stronger capping inversion has the effect of slowing the growth rate of the boundary layer, ultimately reducing the
occurrence during low snow years, are likely to cater to environments that support and maintain intense, low-level rotational centers, thereby increasing the likelihood of supercell tornadogenesis. Another effect of warming the 700-mb level, given identical surface conditions, is to reduce the depth of the afternoon mixed layer. An implied increase in potential temperature jump across the stronger capping inversion has the effect of slowing the growth rate of the boundary layer, ultimately reducing the
