SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Mon May 26 2025 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM WEST CENTRAL TEXAS TO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Severe storms are expected from west-central Texas eastward into the lower Mississippi Valley. Areas of large hail will be possible with the primary risk becoming damaging winds. Marginally severe storms will also be possible outside the Slight Risk area from the southern Plains into the Southeast. ...Texas to the lower Mississippi Valley... Large-scale height field will gradually be suppressed across the southern Plains during the day1 period as upper troughing over the southwestern U.S. advances east. This subtle change should allow the primary synoptic front to gradually sag southeast, along with the focus for organized severe. Early this morning, an elongated corridor of scattered strong-severe thunderstorms extended from AL, arcing into the Arklatex, then west into the southern Plains. The western edge of this activity is expected to gradually expand in areal coverage as an MCS evolves and propagates across north central TX by sunrise. The MCS, or some rejuvenated variant, will spread across the lower MS Valley during the day as modest southwesterly 500mb flow translates across LA into MS. While some weakening is likely after sunrise, boundary-layer heating may contribute to robust development along the leading convective outflow. Damaging winds, and perhaps some hail, are possible with this activity. Upstream, potentially stronger updrafts are expected with convection that develops along the northeastern edge of a steep low-level lapse rate plume. Models insist strong surface heating will occur across far West TX into the Edwards Plateau. Convective temperatures should easily be breached along/south of the synoptic front that will be draped across this region. Supercells should be the initial storm mode, and very large hail will likely be generated as seasonally strong buoyancy will exist across this region. Forecast sounding for SJT at 27/00z exhibits 3000 J/kg MLCAPE with 40kt 0-6km shear, and PW values around 1.5 inch. Convection that develops across this region should propagate southeast, possibly evolving into an MCS during the evening. Probabilities may need to be increased across this portion of TX in subsequent outlooks. ..Darrow/Thornton.. 05/26/2025