Convective Initiation Along Quasi-Stationary Surface Front and Later Envigorated Forcing from Ensuing Outflow Boundaries, June 13th, 2008

Friday the 13th was not so unlucky for the Central Permian Basin as much needed moisture occurred due to the interplay of a trailing weak cold front, extending across the Permian Basin, from an intense Upper Level Low over the Midwest US and subsequent forced lifting from convective complex outflows. Thermodynamic parameters (not as impressive as the previous day where MLCAPE values were much higher and shear profiles stronger coupled with a sharper dryline) were not particularly impressive although a weaker capping inversion existed and if overcome development seemed probable. A Surface Low was located over the Davis Mountains, inducing convergence, and the upper air pattern was controlled by anti-cyclonic circulation centered in northern Mexico, south of Presidio, providing west-northwest to east-southeast wind directional shear aloft. Low level moisture was present, marginally, in the Central Permian Basin with surface dewpoints in the upper 40's to lower 50's, east of drier air in the western Permian Basin, additionally mid-level mositure was noted from water vapor imagery. At around 2300Z convection initiated along a quasi-stationary surface boundary, stalled cold front to slightly retreating warm front, southeast of Midland and extending along a transect from north central Crane to south central Howard counties. The first image is taken near the intersection of FM 1213 and FM 715, south of Midland, looking east northeast, at developing high based convective initiation in northwestern Glasscock county. The second image is looking southeast in southern Midland county at feeder inflow band and associated updraft of developing storm tower, followed by a zoomed image of same. Rapid intensifi-cation ensued, principally in south central Howard county, along the frontal boundary. Due to the high Lifting Condensation Level and subsequent evaporation of descending rain, a strong outflow boundary developed from the Howard county complex and began spreading southwestward toward Midland and Ector counties. This outflow boundary coupled with a now dominantly retreating warm front and impinged against drier air, west, (along dryline boundary) provided excellent lift into mid levels where lapse rates were steep. The next image is taken atop a multi-storied parking garage in downtown Midland at approximately 0200Z, looking northwest, at cloud to ground lightning from developing storm.