Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 08 2025 05:56:04 ACUS02 KWNS 080555 SWODY2 SPC AC 080554 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Mon Sep 08 2025 Valid 091200Z - 101200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS.... ....SUMMARY... Isolated severe storms are possible over the central and southern High Plains Tuesday. ....Synopsis... Amplified mid-level flow will be in place over much of the US Tuesday, as a broad upper low continues to deepen over the Northwest. To the east, shortwave ridging is forecast to intensify over the central Rockies and High Plains, while broad and incoherent troughing persist over the eastern half of the CONUS. Southwesterly mid-level flow will gradually increase over the central High Plains as a series of weak embedded perturbations pass through the crest of the upper ridge. This will aide in strengthening a lee trough, supporting south/southeasterly low-level flow and some severe storm potential. ....Central and Southern High Plains... As the mid-level ridge continues to build over the Rockies and adjacent Plains, a lee trough is expected to sharpen from western SD into the TX Panhandle. Continued low-level southerly flow will advect seasonably rich moisture along and east of this feature, supporting diurnal destabilization with 2000-2500 J/kg of MLCAPE available. However, forcing for ascent from several weak perturbations passing through the top of the ridge is likely to remain nebulous and displaced westward of the primary surface trough axis. Residual capping, and the lack of broader synoptic support is expected to limit diurnal thunderstorm development over the Plains. Eventually isolated development is expected along the lee trough by early evening, aided by an increase in the southerly low-level jet. If these storms can become sustained, marginal supercell wind profiles would support a risk for large hail and strong gusts from western KS and southeastern CO into the OK/TX Panhandle vicinity. Still, substantial uncertainty remains regarding the coverage of any stronger storms able to develop. Have introduced a 5% risk for hail and wind potential. To the west of the surface trough, strong heating and weak ascent should allow isolated to widely scattered, likely high-based, thunderstorms to develop over the higher terrain of CO/WY and adjacent High Plains Tuesday afternoon. Steep low-level lapse rates could support an occasional severe gust with this activity, but limited buoyancy and modest flow aloft suggest little organized severe threat. ....Upper Midwest... A weak surface boundary/cold front will extend from eastern SD into northwestern IA and south-central MN Tuesday. Low-level warm advection atop this boundary in a modestly sheared and weakly unstable environment will support periods of showers and thunderstorms as the front slowly sags southward. Overall severe potential is expected to remain low as convection should remain to the cool side of the boundary and likely be elevated. But, a stronger storm or two could develop and produce small hail or locally gusty winds over portions of eastern SD and western MN. ...Lyons.. 09/08/2025 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .