Wednesday, 9 November 2016: 5:45 PM
Pavilion Ballroom East (Hilton Portland )
Little previous work exists comparing precipitation structure (Low Precipitation, Classic, and High Precipitation) with respect to the impact on tornadogenesis in supercell thunderstorms. It is understood that the relative amount of precipitation falling in and around a supercell thunderstorm’s rotating updraft affects the processes leading toward tornadogenesis. Substantial inconsistencies in radar-derived quantities used to approximate rotation, such as azimuthal shear, tangential velocity, and circulation, across storm types may be indicative of differing dynamical processes and resultant occurrence of tornadogenesis. This study compares two groups of tornadic supercell cases: one group of classic (CL) supercells and one of high precipitation (HP) supercells. All cases occurred from the period 2011 to 2015, after the dual-polarization upgrade of the Weather Surveillance Radar-88D (WSR-88D) network, with strict classification and selection criteria for both groups of cases, such as distance from the WSR-88D site. The cases are analyzed using a single-Doppler radar wind analysis, which is used to calculate circulation and tangential velocity, as well as the National Severe Storms Laboratory (NSSL) Multi-Radar Multi-Sensor (MRMS) program’s recently updated azimuthal shear product. For both individual cases and each supercell type, the similarities and differences of these storm characteristics, with respect to the temporal structural evolution of the vertical mesocyclone, are discussed.
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