A Multi-dataset Analysis Of The Morphology Of Mesoscale Convective Vortices

Mesoscale convective vortices (MCVs) lead to one mode of downstream progression of organized convection on time scales sometimes covering many diurnal cycles. The means by which this occurs is likely through mesoscale vertical motion induced as the vortex interacts with ambient vertical shear. Detection of MCVs and investigation of their structure and influence on convection is complicated by the fact that their scale (100-200 km across) is too large for MCVs to be adequately sampled by a single Doppler radar scan, but too small for MCVs to be captured routinely by rawinsonde and profiler data.

We present results from the 1998 and 1999 convective seasons over the central U.S. in which operational data from the WSR-88D radar network, GOES Rapid Scan, and the NWS Family of Services were employed document the frequency of occurrence, structure and evolution of MCVs and the subsequent convection they engender. Winds deduced from cloud tracking and movement of radar echoes prove crucial for detailing the structure of MCVs. Animations of satellite and radar data allow for improved detection, resulting in an estimated MCV frequency of 15-20 per year, as contrasted with 2-4 per year reported in previous studies. A detailed, multi-dataset analysis is presented for the MCV case of 27-29 May, 1998, in which an MCV spawned over North Texas was responsible for heavy rain events further downstream on each of the succeeding two nights.