Vertical Wind Shear Associated with Left-Moving SupercellsSource: Weather and Forecasting:;2002:;volume( 017 ):;issue: 004::page 845Author:Bunkers, Matthew J.
DOI: 10.1175/1520-0434(2002)017<0845:VWSAWL>2.0.CO;2Publisher: American Meteorological Society
Abstract: Vertical wind shear parameters are presented for 60 left-moving supercells across the United States, 53 of which produced severe hail (≥1.9 cm). Hodographs corresponding to environments of left-moving supercells have a tendency to be more linear than those of their right-moving supercell counterparts. When curvature is present in the hodographs of the left-moving supercells, it is typically confined to the lowest 0.5?1 km. Values of 0?6-km wind shear for left-moving supercells?both bulk and cumulative?are within the ranges commonly found in right-moving supercell environments, but the shear values do occur toward the lower end of the spectrum. Conversely, the absolute values of storm-relative helicity (SRH) for left-moving supercells are much smaller, on average, than what occur for right-moving supercells (although SRH values for many right-moving supercells also fall well below general guidelines for mesocyclone development). A significant fraction of the 0?3-km SRH (25%) and 0?1-km SRH (65%) for left-moving supercells is positive, owing to the shallow clockwise curvature of the hodographs. However, nearly all of the 1?3-km SRH for left-moving supercells is negative, with absolute values comparable in magnitude to those for right-moving supercells. A limited climatological analysis of vertical wind shear associated with convective environments across parts of the central United States suggests that clockwise curvature of the low-level shear vector is most common in the central/southern plains, partially explaining the preeminence of right-moving supercells in that area. In contrast, hodographs are more linear over the northern high plains, suggesting left-moving supercells may be relatively more common there. It would be beneficial to implement operational radar algorithms that can detect mesoanticyclones across the United States.
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contributor author | Bunkers, Matthew J. | |
date accessioned | 2017-06-09T15:02:12Z | |
date available | 2017-06-09T15:02:12Z | |
date copyright | 2002/08/01 | |
date issued | 2002 | |
identifier issn | 0882-8156 | |
identifier other | ams-3269.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4170278 | |
description abstract | Vertical wind shear parameters are presented for 60 left-moving supercells across the United States, 53 of which produced severe hail (≥1.9 cm). Hodographs corresponding to environments of left-moving supercells have a tendency to be more linear than those of their right-moving supercell counterparts. When curvature is present in the hodographs of the left-moving supercells, it is typically confined to the lowest 0.5?1 km. Values of 0?6-km wind shear for left-moving supercells?both bulk and cumulative?are within the ranges commonly found in right-moving supercell environments, but the shear values do occur toward the lower end of the spectrum. Conversely, the absolute values of storm-relative helicity (SRH) for left-moving supercells are much smaller, on average, than what occur for right-moving supercells (although SRH values for many right-moving supercells also fall well below general guidelines for mesocyclone development). A significant fraction of the 0?3-km SRH (25%) and 0?1-km SRH (65%) for left-moving supercells is positive, owing to the shallow clockwise curvature of the hodographs. However, nearly all of the 1?3-km SRH for left-moving supercells is negative, with absolute values comparable in magnitude to those for right-moving supercells. A limited climatological analysis of vertical wind shear associated with convective environments across parts of the central United States suggests that clockwise curvature of the low-level shear vector is most common in the central/southern plains, partially explaining the preeminence of right-moving supercells in that area. In contrast, hodographs are more linear over the northern high plains, suggesting left-moving supercells may be relatively more common there. It would be beneficial to implement operational radar algorithms that can detect mesoanticyclones across the United States. | |
publisher | American Meteorological Society | |
title | Vertical Wind Shear Associated with Left-Moving Supercells | |
type | Journal Paper | |
journal volume | 17 | |
journal issue | 4 | |
journal title | Weather and Forecasting | |
identifier doi | 10.1175/1520-0434(2002)017<0845:VWSAWL>2.0.CO;2 | |
journal fristpage | 845 | |
journal lastpage | 855 | |
tree | Weather and Forecasting:;2002:;volume( 017 ):;issue: 004 | |
contenttype | Fulltext |