SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0217 AM CST Thu Nov 13 2025 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE UPPER OH VALLEY VICINITY... ...SUMMARY... Isolated damaging winds are possible during the late afternoon to evening Saturday across the Upper Ohio Valley vicinity. ...Upper OH Valley to the Mid-Atlantic States... Amplification of a large-scale upper trough appears probable from the Canadian Prairies across the Great Lakes towards the Northeast through early Sunday. This will induce a deepening surface cyclone from Lake Superior/northern ON towards New England. Trailing to its southwest will be a sharpening cold front that should accelerate southeastward. With only modified boundary-layer moisture return (emanating from east TX and LA) ahead of the front, MLCAPE should be quite limited and spatially confined to the OH vicinity. But intensifying tropospheric wind profiles, coupled with the increasing large-scale ascent along the front, are concerning for a conditional threat of at least damaging winds where surface-based convection can develop. Guidance consensus suggests this may occur towards late afternoon and especially into the evening across the Upper OH Valley. East of the Appalachians, development of surface-based instability appears unlikely Saturday night, although elevated convection may persist towards parts of the coastal Mid-Atlantic. ...Southwest... The drifting upper low off the southern CA coast should evolve back into an open trough that accelerates northeastward by 12Z Sunday. This will lead to the mid-level cold core finally moving inland, aiding in steepening of lapse rates. The low-level warm conveyor will likewise shift east across the Lower CO Valley and Mojave Desert. This setup will support a broadening of isolated thunder potential from southern CA into western AZ and far southern NV by Saturday night. ..Grams.. 11/13/2025
