SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 PM CST Wed Dec 17 2025 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential will be limited today, but isolated strong wind gusts are possible across portions of the Lower Ohio and Tennessee Valleys. ...Lower Ohio/TN Valleys... Strong midlevel trough is advancing quickly across the northern/central High Plains late this evening. This feature is forecast to progress into the MS Valley by late afternoon then eject negative-tilt into the OH Valley during the overnight period. Intense 12hr height falls, on the order of 210m, will spread across the OH Valley and this is expected to aid large-scale forcing along a sharp cold front that will surge into IN/KY/TN by 19/00z. Poor destabilization is expected ahead of the front and forecast soundings exhibit meager instability, and this is mostly with an elevated parcel. While buoyancy will be weak, a strongly forced band of frontal convection is expected to develop and spread east. Given the level of parcel ascent, current thinking is a stable boundary layer will minimize the risk of severe gusts near the surface. Even so, isolated strong winds may accompany some portions of the convective line, but the risk of severe gusts in excess of 50kt appears too low to warrant a MRGL risk at this time. ..Darrow/Wendt.. 12/18/2025
