Preliminary High-Resolution Dual-Doppler Analyses of Two Tornadic Thunderstorms

Data with high spatial and temporal resolution from two Doppler on Wheels (DOW) radars are synthesized to study the wind field of two thunderstorms prior to the genesis of and during the mature stage of intense (F3) tornadoes. The tornadoes considered occurred on June 3, 1999 near Almena, KS and on May 17, 2000 near Brady, NE. In both cases, volumetric data are used to compute derived quantities such as the vertical vorticity, the circulation, convergence, and individual terms in the vertical vorticity equation. These are compared in the pre-tornadic and mature tornadic stages of the thunderstorms. The structures of the wind fields associated with the mesocyclone and tornado are examined and compared for the two cases. The dual-Doppler syntheses are compared to conceptual and computer models of tornadic storms. Several structures predicted to exist in association with mature supercellular tornadoes are documented with vector wind field observations.