Extended Abstract (380K)10.5
How upper-level shear can promote organized convective systems
Michael C. Coniglio, NOAA/NSSL/University of Oklahoma, Norman, OK; and D. J. Stensrud and L. J. Wicker
This study examines the role of positive mid-and upper-level vertical wind shear on the lifting of environmental air along cold pools. Observations of strong, linear convective systems within relatively weak low-lever shear and significant mid- and upper-level shear that may not fit past conceptual models of cold pool/shear interactions will be presented. By using a numerical cloud model in a 2D dry, nuetral state, it is found that increasing the shear above the cold pool can promote much deeper lifting than an environment with only weak to moderate low-level shear. As suggested in previous analytical studies, vertical parcel displacements are increased, despite a decrease in vertical velocity along the leading edge of the cold pool. Positive wind shear in the 5-10 km layer can promote deeper lifting by this same mechanism for parcels originating in the 1-2 km layer. Moist 2D and 3D simulations that include ice microphysics also suggest this mechansim can significantly influence the maintenance and structure of convective systems.
Session 10, Synoptic and Mesoscale Processes and Severe Convection
Wednesday, 6 October 2004, 1:30 PM-3:00 PM
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