Subj : DAY1SVR: Day 1 Convective To : All From : Mike Powell Date : Wed May 03 2023 15:42:00 ACUS01 KWNS 031957 SWODY1 SPC AC 031956 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Wed May 03 2023 Valid 032000Z - 041200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH EVENING ACROSS THE PECOS VALLEY AND PERMIAN BASIN OF WEST TEXAS... ....SUMMARY... Isolated large hail and strong-severe outflow winds will be possible through this evening across the Pecos Valley and Permian Basin of west Texas. ....20z Update... A minor adjustment to the Marginal risk has been made over northwest Texas with the 20z update. Isolated convection has developed this afternoon along an outflow-reinforced boundary. Modified RAP soundings with current observations indicate a somewhat more favorable environment exists within the frontal zone compared to earlier forecast guidance. A storm or two may briefly become severe, producing marginal hail and strong gusts. For more info on short term severe potential, see MCD 670. Otherwise, the previous forecast remains on track. For short term severe information across the Trans-Pecos/Permian Basin see MCD 671. ...Leitman.. 05/03/2023 ..PREV DISCUSSION... /ISSUED 1111 AM CDT Wed May 03 2023/ ....Southern High Plains this afternoon through late evening... Midlevel ridging will persist over the High Plains, between deep midlevel lows near the central CA coast and over western NY/PA. A convectively enhanced trough and associated elevated convection has moved through the mean ridge, and will continue slowly eastward over southern OK today. The rain/clouds with this wave will reinforce a baroclinic zone just south of the Red River, which will demarcate the northern fringe of the boundary-layer dewpoints above 60 F. Farther west, the flow regime will encourage only weak lee troughing from eastern NM into eastern CO, with modest low-level moisture (dewpoints in the mid 40s to mid 50s) along and east of the weak lee trough. Satellite imagery shows a large area with few/no clouds centered over eastern NM, so strong surface heating/mixing is expected along the lee trough, and in the immediate lee of the higher terrain features such as the Davis/Guadalupe/Sacramento Mountains northward to the Raton Mesa. Weakening convective inhibition and MLCAPE in the 1000-1500 J/kg range will favor high-based thunderstorm development, some of which could be splitting supercells given relatively straight hodographs and effective bulk shear in the 30-35 kt range. The initial/supercells storms will be capable of producing isolated large hail (mainly 1 to 1.75 inches in diameter) and strong/severe outflow gusts. There will be some potential for upscale growth into a small cluster across the South Plains/TX Panhandle tonight as low-level warm advection strengthens, though the severe threat will slowly diminish by late evening. ....Great Basin/Pacific Northwest... Some high-based convection will be possible this afternoon across western UT, around the eastern periphery of the northern CA closed low. Moisture will be limited, but deep inverted-v profiles and minimal buoyancy could support strong outflow winds for a few hours this afternoon/evening. Other isolated strong/elevated storms may occur in the eastern flow regime north of the closed low (along the Cascades), where steep midlevel lapse rates support weak buoyancy. $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .