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.

Discrete SuperCell Along Weak Surface Cold Front Surface Boundary, Reagan County, June 9th, 2008

Convective initiation began in late afternoon-early evening in the southeastern Permian Basin along and south of a weak surface cold front in moist lower levels and moderately unstable air aloft (MUCape values near 2000 J/kg), due to Upper Level amplified troughing to the north which when coupled with surface heating had eroded convective inhibition. All following images were taken from Midland looking southeast at developing storms, approximately 5o miles distant, in Reagan and Irion counties with a 70-300mm lens. The first image is zoomed at developing convective growth in Reagan county at approximately 0130Z. This cell became severe warned by NWS/MAF shortly afterward. Two additional images after warning occurred, noting crispness of intensification, (1) and overshooting top above vertical scalloped striations atop initial anvil spreading, (2). The next image is of a radar capture of the cell in Reagan county with well developed V-notch and also noting weaker cell in Irion county to the east of previous photographed storm. The next image is of the Irion county cell as viewed from behind, northwest, with back building convective towers. The next image is from the Reagan county cell, nearing dusk, showing hint of overshoot-ing top from main storm tower updraft above spreading anvil with back building smaller towers in foreground. The last capture is an un-zoomed image of the Reagan county cell during maturing stage.

Dry-Line Thunderstorms, Eastern Permian Basin, June 5th, 2008

Thunder-storms began to develop late afternoon early evening along a well defined dry-line in the eastern sector of the Permian Basin, along the southern said boundary, associated with an intense Upper Level Low centered in the central Rockies. The Upper Level Low and associated short wave troughs broke down an entrenched Upper-mid Level High which had controlled the weather across the Permian Basin for several days with above normal temperatures, exceeding the century mark. Low level moisture was present early in the morning and early afternoon hours, extending into the central Permian Basin but was gradually displaced eastward by strong westerly winds mixing downward from the base of the Upper Level Low, advancing from the western US. At 2000Z the author drove to Big Spring awaiting dry-line initiation where cumulus clouds had developed along the dry-line but mid level capping inversion was still in place preventing storm tower growth. The first image is a screen capture from the truck at previously mentioned locale depicting surface winds and defining dry-line with intersection of same and SPC depicting thunderstorm probability east of Midland. After watching the dry-line locale with cumulus cloud development for one hour, with no storm tower development, the author had to return to Midland. Later in the evening storm tower and organized cell development occurred. The next image was taken at 0115Z in a parking lot in Midland looking east-northeast at dry-line induced convection. The next image is a zoom of storm tower growth. The next image is radar capture of dry-line initiation represent-ing the previous photo-graphs delineating the northeast aligned, parallel to dry-moist boundary, eruption. The next image is a regional radar capture of storm develop-ment along dry-line with surface wind convergence overlay. The last image is a radar regional view of previous but showing 24,000 ft winds aloft, denoting 60 knot energy, rounding the southern periphery of the Upper Level Low overlapping with the surface to 850MB level dry-line boundary.