Mesocyclone evolution as seen by airborne pseudo-dual Doppler radar during vortex

The Verification of the Origin of Rotation in Tornadoes EXperiment (VORTEX) was conducted in the spring of 1994 and 1995 in Oklahoma, Texas, and Kansas. The aims of VORTEX were tightly focused on the issues of tornadoes and tornadic storms. Since the objectives of VORTEX required knowledge of the 4-D flow structure only in the small region around the low- and middle-level mesocyclone, 'ground-up' integrations of the continuity equation were performed only in the lowest few kilometers of the storm to determine the vertical component of velocity. Hence, poor radial velocity estimates at high altitudes were not a major concern. The first priority is to obtain 4-D vertical vorticity analyses, and if possible, analyses of vector vorticity and vorticity budget terms. It should be noted that a preliminary analysis of the low-level velocity fields reveals very strong horizontal vorticity just ahead of the mesocyclone along the gustfront. This vorticity may be the source of rotation for the tornado if it was tilted abruptly near the ground.