P1.1 Study of microphysical and thermodynamic structures within supercell thunderstorms

Monday, 17 August 2009
Arches/Deer Valley (Sheraton Salt Lake City Hotel)
Katja Friedrich, University of Colorado, Boulder, CO; and J. Wurman and K. A. Kosiba

Improved predictability of severe storm behavior is expected to emerge from a better understanding of storm evolution dependence on microphysical and thermodynamic characteristics, which to date remains relatively unknown. A wide array of ground-based instrumentation is used to examine the characteristics of supercell thunderstorms in the Great Plains during the Radar Observations of Tornadoes And Thunderstorm Experiment 2008 (ROTATE) and the Verification of the Origins of Rotation in Tornadoes Experiment 2009 (VORTEX2). High-resolution radar observations close to the area of tornado formation are combined with mobile disdrometer measurements, and surface observations of wind, temperature and humidity to map low-level cold pool and local storm environment characteristics. The mobile disdrometers were deployed ahead of areas of interest within supercells, such as just downstream of the hook appendage measuring transects of particle size distribution and fall velocity distribution through the storm. The presentation will show time-space variation of particles size distribution of different storms and during various stages in storm evolution and a detailed analysis of microphysical and thermodynamic features within a tornadic supercell occurring near the town of Ness City, Kansas, on 23-24 May 2008 between 2345 – 0030 UTC. Several vortices and a weak tornado < 1 km wide with maximum Doppler velocity of ±30 m s-1 moving northeastwards developed within this thunderstorm. Nine unmanned surface observation platforms measuring wind, pressure, temperature, and humidity aligned in east west direction were place ahead of this tornado few minutes before its passage. The analysis results will be compared to the microphysical and thermodynamic characteristics of other tornadic supercell thunderstorm observed during ROTATE 2008 and VORTEX2 2009.
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