SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1230 AM CDT Thu Mar 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MISSOURI/MID-MISSISSIPPI VALLEY REGION...AND SOUTH TEXAS... ...SUMMARY... Multiple rounds of severe thunderstorms are possible in south Texas with hail and wind as the primary hazards. Across parts of the Lower Missouri/Mid-Mississippi Valleys, isolated to scattered large hail and localized severe gusts are possible, mainly during the late afternoon and evening. ...South Texas... Complex, slow-moving upper trough will eject across northern Mexico toward deep South TX by the end of the period. Strongest mid-level flow will translate through the base of the trough, south of the international border into the lower Valley of TX by early evening. LLJ will remain focused across south TX and multiple rounds of deep convection are expected during the day1 period. Adequately buoyant, and modestly steep lapse rate environment favors robust updrafts, as deep layer shear will support storm organization. Hail/wind appear to be the main threats with this activity, though a brief tornado or two can not be ruled out. ...Lower MO/Mid-MS Valleys... Upper ridge is forecast to flatten a bit by the end of the period, though heights will remain neutral to slight rises. As a result, mid-level flow should back to a more westerly orientation with a few weak disturbances expected to translate across the northern Plains toward the mid/upper MS Valley. This flow regime will maintain a notable, but veered, LLJ from western KS into eastern IA through the period. Primary corridor of low-level warm advection will thus be oriented across the upper Red River region into the lower OH Valley. This corridor will likely experience multiple bouts of elevated convection, driven in large part by the aforementioned LLJ. Steep mid-level lapse rates will overspread this region and thermodynamic profiles will prove at least somewhat supportive of robust updrafts capable of generating hail at times. However, of potentially more concern will be convection that develops during the late afternoon along the eastern-most plume of steep low-level lapse rates, from northeast KS/southeast NE into southwest IA. Latest model guidance suggests inhibition will weaken such that isolated thunderstorms may try to initiate by 23-00z. Wind profiles favor organized updrafts and potential supercell development. However, additional thunderstorm activity should be noted downstream within the stronger warm advection corridor during the overnight hours, though updrafts will be elevated in nature. ..Darrow/Lyons.. 03/27/2025