
SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0743 AM CDT Thu Mar 13 2025 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST MISSISSIPPI SOUTHEAST ACROSS ALABAMA AND INTO THE FLORIDA PANHANDLE AND WESTERN GEORGIA... ...SUMMARY... A few severe thunderstorms producing hail and locally damaging gusts are possible from eastern Mississippi into Alabama, western Georgia, and parts of the Florida Panhandle today. ...Synopsis... Water-vapor imagery this morning shows a convectively enhanced mid-level vorticity max near the AR/TN/MS border and located within a larger mid-level trough centered over the lower MS Valley. The mid-level trough will move southeast over the FL Peninsula by mid evening with the strongest accompanying belt of mid-level flow shifting into the northern and eastern parts of the Gulf. Farther west, a mid-level ridge will move east across the Great Plains into the MS Valley as an intensifying trough quickly moves east across southern CA to the southern High Plains during the period. A cold front will push east across the lower CO Valley and Sonoran Desert. ...Northwest Mississippi, Central/Southern Alabama, western Georgia and the western Florida Panhandle... South-southwesterly low-level flow this morning is acting to advect modestly more moisture (950-925 mb layer) into the region this morning (reference 12 UTC Jackson, Birmingham, and Slidell, LA raobs). This moisture is beneath the eastern fringe of an elevated mixed layer that features steep 700-500 mb lapse rates (7.5 to 8.5 deg C/km per raob data). Ongoing cluster of showers/storms over northern MS will probably slowly develop southeast through midday. Ample heating to the south/southwest of northwest to southeast-oriented surface trough will contribute to MLCAPE around 500-1000 J/kg. As the zone of ascent overspreads the destabilizing airmass across AL into GA/FL, additional storms are forecast this afternoon. Isolated to scattered storm coverage is forecast and a few of the stronger storms will potentially yield an isolated threat for severe. This activity will likely weaken by evening owing to the loss of heating and departing large-scale ascent. ...Southern Arizona... As a cold front progresses across southern Arizona, shower and thunderstorm activity is expected to spread across the region. Flow aloft will be quite strong, as a 100 kt jet max digs southward across the Mexico border. It is possible some higher momentum flow may mix down to the surface at times for a gust to approach severe limits within convection. Overall, the weak thermal profile would suggest the severe threat will remain low. ..Smith/Dean.. 03/13/2025