SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Fri Mar 15 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTH-CENTRAL TEXAS AND THE MISSISSIPPI/ALABAMA REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible across portions of south-central Texas and over parts of Mississippi/Alabama region. ...South-central TX... Confluent high-level flow over the middle of the CONUS will encourage surface anticyclone to settle south across the Plains today, though some weakening is expected across the southern Plains late in the period. Latest water-vapor imagery suggests a weak midlevel short-wave trough is approaching south TX early this morning. This feature is forecast to advance into the lower MS by 18z as associated 500mb speed max translates downstream into the central Gulf States. As a result, neutral-weak height rises are expected across south-central TX by afternoon. As this low-latitude short wave approaches higher-quality moisture, there is some concern that early-day elevated convection may develop. Several HREF members suggest isolated supercells initiate ahead of this feature. However, forecast soundings are quite capped so any activity should remain isolated. Of more concern is the strong surface heating anticipated across northeast Mexico into portions of south TX ahead of the synoptic front. Forecast soundings ahead of the boundary suggest convective temperatures will be breached as readings warm into the lower 80s. NAM sounding for DRT at 22z exhibits negligible CINH with SBCAPE on the order of 2500 J/kg with a temp/dew point of 83/62F. Strong surface-6km bulk shear and weak frontal convergence favor thunderstorm development and supercells appear possible. Large hail, some of it potentially bigger than 2 inches, is the primary risk with these storms. While convection should initiate due to strong heating, thunderstorms will likely linger well into the overnight hours as an increase in the LLJ is expected during the latter half of the period into this portion of TX. ...MS/AL... Southern-stream short-wave trough will approach the lower MS Valley around 18z before advancing into the southern Appalachian region by 16/00z. In response to this feature, LLJ will be focused across MS/AL early, then veer into the west across GA as the short wave progresses downstream. Synoptic front will likely prove instrumental in convective development as it advances slowly southeast across the Gulf States. Forecast profiles suggest organized convection is possible, with some risk for supercells given the strong shear and modest buoyancy. While low-level SRH is not particularly strong, a tornado or two can not be ruled out with this activity, though damaging winds may be the greatest risk. ..Darrow/Wendt.. 03/15/2024
