SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Sat Mar 15 2025 Valid 151630Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MISSISSIPPI AND ALABAMA... ...SUMMARY... A tornado outbreak is expected today across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes, some of which should be long-track and potentially violent, are expected this afternoon and evening. The most dangerous tornado threat will begin across eastern Louisiana and Mississippi through this afternoon, spread across Alabama this afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. ..Gleason/Squitieri.. 03/15/2025
