Monday, 5 November 2012
Symphony III and Foyer (Loews Vanderbilt Hotel)
Jared L. Guyer, NOAA/NWS/SPC, Norman, OK; and J. A. Hart
Among other factors, it is well-established that influences of at least sufficiently strong vertical shear and storm relative helicity (SRH) within the lowest 1-2 km AGL are important ingredients with respect to supercells that produce tornadoes. Observationally monitoring temporal trends and relatively fine-scale changes of low-level shear and SRH, through means such as Weather Surveillance Radar-1988 Doppler (WSR-88D) network derived VAD (Velocity Azimuth Display) Wind Profile (VWP) and wind profiler network data, are of prime importance to operational forecasters at the Storm Prediction Center (SPC) and other National Weather Service (NWS) offices.
A multi-year (2008-2011) WSR-88D VWP dataset is used to examine the magnitude and temporal trends of low-level shear and SRH associated with tornadic environments. Of particular focus are observed supercells over the contiguous United States that produced strong tornadoes (EF2 and greater) within close proximity (<75 km) to a network WSR-88D. In aggregate, these data help resolve the fine-scale variability and low-level wind trends near supercells associated with strong tornadoes. While many prior studies have utilized observed proximity soundings and/or model-based (e.g. RUC) analyses, this WSR-88D VWP-based analysis provides additional observationally-based insight into the low-level wind profiles of near-storm environments associated with strong tornadoes.
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