SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 PM CST Fri Nov 14 2025 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY... ...SUMMARY... Showers and a few thunderstorms may be accompanied by strong wind gusts across parts of the upper Ohio Valley late this afternoon and evening. ...Ohio Valley... Strong large-scale midlevel height falls will spread across the Great Lakes/Ohio Valley later today in advance of a short-wave trough that will dig into the Great Lakes by 16/00z. Associated cold front will surge to a position from southern ON-northern OH-central IN by late afternoon and this feature is expected to serve as the focus for isolated thunderstorms. Latest model guidance is not particularly aggressive in boundary-layer destabilization with surface temperatures forecast to warm into the lower 60s along the OH river into southern OH, with upper 50s expected downstream across western PA. These temperatures would yield a few hundred J/kg uncapped SBCAPE by late afternoon within a strongly sheared environment. HREF guidance suggests weak frontal convection should evolve between 16/00-02z across eastern OH/western PA. This activity will spread downstream, but likely weaken fairly quickly in the absence of meaningful buoyancy over central PA. Strong wind gusts are the primary concern. ...Southern CA... Strong 500mb speed max will translate through the base of the offshore trough toward the northern Baja Peninsula by 18z, with high-level diffluent flow forecast across southern CA/lower CO River Valley. Latest guidance suggests the associated cold front will surge inland after 18z-19z, and cooling post frontal profiles will lead to a bit more instability that should favor lightning within deeper convective updrafts. Pre frontal convection is expected to be weakly buoyant and updrafts should reflect this poor instability air mass. While post frontal destabilization may lead to more robust updrafts, weaker shear does not appear particularly favorable for severe wind, but some small hail could be noted. Will not introduce severe probabilities for these reasons. ..Darrow/Moore.. 11/15/2025
