1PM Day 3 Convective Outlook for Friday, February 13. THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF WEST TEXAS
SUMMARY
Isolated strong to severe thunderstorms could produce small to marginally severe hail Friday evening into the overnight hours across portions of western Texas.
Synopsis
Positively tilted upper troughing is expected to extend from the western Great Basin southwestward into the east-central Pacific Ocean early Friday morning. Two shortwave troughs are forecast to be embedded within this larger troughing. The southernmost shortwave trough expected to progress quickly eastward through the base of the parent troughing before then pivoting more northeastward at it moves into the eastern periphery of the troughing over northern Mexico. The northernmost shortwave trough will be less progressive at it moves across southern CA and the Lower CO Valley. Evolution of the system will likely result in a relatively consolidated southern-stream trough extending from the central High Plains southwestward through northern Mexico by early Saturday.
West TX
Downstream mass response will result in considerable airmass modification across the southern Plains ahead of this system, with upper 50s dewpoints likely reaching through much of west TX by Friday evening. Afternoon temperatures will likely reach the low 70s, which will combine with the increasing moisture and cooling mid-level temperatures to support modest buoyancy (i.e. 500 to 1000 J/kg of MLCAPE). The stronger forcing for ascent associated with the approaching wave will likely lag peak heating slightly, but a few surface-based storms are still possible amid weak capping and low-level convergence. Supercell wind profiles, characterized by modest low-level southeasterlies and moderate/strong southwesterlies aloft, suggest that any storms that do develop could organize and become severe. Large hail would be the primary hazard.
Thunderstorm coverage will likely increase as stronger ascent associated attendant to the approaching wave and a strengthening low-level jet arrives during the evening. Given anticipated nocturnal stabilization, much of this activity will likely be elevated, but strong deep-layer shear could still support updrafts capable of isolated hail.
Northwest TX into OK
Strengthening low-level southerly flow and moistening low levels ahead of the approaching wave will contribute to increasing showers and thunderstorms from northwest TX into much of OK Friday evening and overnight. Poor mid-level lapse rates will result in weak buoyancy, but moderate vertical shear could still contribute to a few stronger updrafts capable of small hail. Severe coverage in this area is currently expected to be less than 5%.