Thursday, 9 November 2006: 2:15 PM
St. Louis AB (Adam's Mark Hotel)
The midlevel kinematic characteristics of two supercell thunderstorms observed during VORTEX, one tornadic and the other nontornadic (the 16 May 1995 and 12 May 1995 cases, respectively), will be compared using ELDORA dual-Doppler wind retrievals. Considerable similarity has been documented in prior dual-Doppler wind syntheses of these two storms in which low-level kinematic traits were scrutinized, although significant differences in the near-ground thermodynamic properties of these storms (e.g., outflow buoyancy and equivalent potential temperature) also have been documented. Downdrafts are widely believed to be important for the formation of tornadoes within supercells in the absence of preexisting near-ground vertical vorticity, and the relative coldness of downdrafts are increasingly believed to be related to the likelihood of tornadogenesis within a supercell. Given that downdraft characteristics ought to depend, at least in part, on the characteristics of the midlevel flow (e.g., strength of rear-to-front flow, entrainment of midlevel dry air), it might be worthwhile to investigate differences in the midlevel kinematic characteristics of nontornadic and tornadic supercells. The 16 May 1995 and 12 May 1995 cases will be showcased in this presentation, although additional cases may be presented, time permitting.
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