


Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
606 ACUS02 KWNS 031732 SWODY2 SPC AC 031731 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Wed Sep 03 2025 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS NORTHWARD INTO NEW YORK... ...SUMMARY... Scattered strong thunderstorms capable of producing locally damaging wind gusts may impact a corridor from the Tennessee Valley and southern Appalachians northward through northern New York on Thursday. ...Synopsis... A deep/vertically stacked low pressure system will retrograde slightly westward over Ontario through the forecast period, while broad large-scale troughing encompasses much of the eastern CONUS. An embedded midlevel trough will track eastward across the Lower Great Lakes during the day, while a related cold front extending from NY south-southwestward along the Appalachians moves gradually eastward. ...TN Valley and Southern Appalachians northward into NY... Despite poor midlevel lapse rates, diurnal heating amid middle/upper 50 to lower 60s dewpoints will result in a corridor of weak to locally moderate surface-based buoyancy ahead of the front during the afternoon. Scattered thunderstorms are expected along/ahead of the front, where 30-40 kt of effective shear will promote loosely organized multicell clusters and line segments. The stronger storm clusters will be capable of producing locally damaging wind gusts through the afternoon. ...Northern Plains... On the backside of the large-scale trough, a robust midlevel speed maximum will move into the northern Plains during the day. Strong forcing for ascent and cold temperatures aloft will support isolated thunderstorms. While deep-layer shear will be sufficient for organized storms, the post-frontal nature of this activity should limit the overall severe risk. ..Weinman.. 09/03/2025 $$