Subj : DAY2SVR: Nws Storm Predic To : All From : Mike Powell Date : Tue Sep 09 2025 08:11:22 ACUS02 KWNS 090554 SWODY2 SPC AC 090552 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Sep 09 2025 Valid 101200Z - 111200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Scattered showers and thunderstorms are possible over parts of the Northwest, northern Rockies with more isolated storms over the High Plains Wednesday. A stronger storm or two is possible, but severe potential is overall low. ....High Plains... East of a deepening upper low and 40-50 kt mid-level jet over the Great Basin and Northwest, shortwave ridging will persist across the Rockies and adjacent High Plains. A broad lee trough is expected to sharpen through the afternoon as weak ascent from the upper trough and mid-level jet glance the western edge of the upper ridge. The strongest ascent will be focused north and west over MT where a weak surface cyclone is expected to form by Wednesday afternoon. This will help draw richer low-level moisture westward later in the afternoon/evening. The late arrival of the more robust moisture suggests buoyancy will be limited, while capping remains stout over the northern and central High Plains. Still, robust heating and sufficient low-level moistening will allow for isolated high-based thunderstorms along the length of the surface trough across eastern MT/WY and western SD. A stray gust or two is possible, but limited buoyancy and forcing suggest the severe risk is low. Farther south, a weak secondary low is expected to form over the Raton Mesa. Enhanced easterly low-level upslope flow could support isolated storms late afternoon or into early evening. However, weak subsidence and warm mid-level temperatures beneath the upper ridge suggest remnant capping is likely to remain in place, limiting storm coverage/intensity. While moderate buoyancy is expected (1500-2500 J/kg) and an isolated stronger gust is possible, overall severe potential appears rather limited. ....Northwest and northern Rockies... Beneath the upper low, broad ascent and the southerly mid-level jet will overspread modest low-level moisture ahead of a weak cold front over the Intermountain West. Filtered daytime heating between remnant cloud cover will aide in scattered storm development across the higher terrain from eastern WA/OR into northern ID and western MT Wednesday afternoon. The increase in southerly flow aloft will elongate mid and upper-level hodographs to some degree, with 20-30 kt of bulk shear expected. This could support a few stronger storms, especially over portions of central ID and into western MT where ascent will be maximized. Given the steep low and mid-level lapse rates, a few strong gusts are possible. However, the threat for more organized/persistent severe storms appears limited by weaker buoyancy (MLCAPE ~500 J/kg) and moisture. ...Lyons.. 09/09/2025 $$ --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1) .