During the afternoon of 19 June 2007 an extremely unstable airmass was located across the Southern Plains as evident by Convective Available Potential Energy (CAPE) values near 7000 J/kg across Oklahoma. Thunderstorms developed across western Kansas, northern Oklahoma, and the Texas Panhandle in response to strong diurnal heating and weak forcing attributed to surface features and a subtle mid-level shortwave. These thunderstorms grew upscale into three mesoscale convective systems (MCS) before merging into one large MCS that pushed into southern Texas and the northern Gulf of Mexico.

In the days that followed, a mesoscale convective vortex (MCV) was observed meandering through the Southern Plains. Daily convection firing in the vicinity of the MCV, combined with a blocking pattern, aided the upscale growth of the MCV to a sub-synoptic scale, warm-core low pressure. During this upscale growth an eastward moving tropical wave brought extremely high precipitable water values (over 2 inches) into the region. The sub-synoptic scale low persisted for well over a week, producing excessive rainfall along its track as it meandered throughout the Southern Plains.

This excessive rainfall event raises many interesting questions. What caused the MCV to stall over the Southern Plains? What impacts did this particular event have on society? What caused the MCV to grow upscale into a warm-core low pressure? What is the name given to such a pattern? This paper will provide a brief overview of the event and begin to address some of the questions arising from such an anomalous pattern.