Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 10 2025 17:36:06 ACUS02 KWNS 101736 SWODY2 SPC AC 101734 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1234 PM CDT Wed Sep 10 2025 Valid 111200Z - 121200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL ROCKIES TO THE NORTHERN PLAINS.... ....SUMMARY... Isolated strong to severe thunderstorms with hail and severe wind potential are possible across portions of the Rockies, central/northern High Plains into the Dakotas and northern Minnesota on Thursday. ....Synopsis... On Thursday, a large trough will be present across the western CONUS with a strong ridge across the Plains and troughing across the east. This pattern will shift slowly east through the day. Surface high pressure will dominate much of the eastern CONUS with lee troughing in the central and northern High Plains. ....Eastern Montana/northern Wyoming into the Dakotas and northern Minnesota... A cluster of storms may be ongoing across northern North Dakota at the start of the period. A moderate low-level jet is forecast to maintain intensity (and perhaps strengthen somewhat) during the day. This may result in maintenance of this cluster and restrengthening during the afternoon across southern Canada and perhaps into northern North Dakota and northern Minnesota. Moderate instability and moderate shear, combined with steep lapse rates, will support the potential for large hail and damaging wind gusts as these storms move east. Cooling temperatures aloft and steep lapse rates will lead to scattered to widespread thunderstorm development across much of the higher terrain across Wyoming and Montana. Modest deep-layer shear and a relatively dry profile will support the potential for some organized storms including supercells. These storms may produce isolated large hail and severe wind gusts. A more conditional severe environment will be present across eastern Wyoming/Montana and into the western Dakotas. Stronger instability (2000 to 3000 J/kg MLCAPE) is forecast across the region, but only weak height falls will be present with at least some residual capping from most forecast soundings. Some weak convergence/confluence will be present along the lee trough/dryline which could initiate a few storms. If storm form within this region, moderate deep-layer shear could support supercells capable of large hail and severe wind gusts. If this scenario appears more likely, a Slight Risk may be needed in later outlooks, particularly across eastern Montana and western North Dakota. ....Central Rockies... Moderate to strong shear will be present across the Rockies as a 45 to 60 knot mid-level jet streak overspreads the region. Weak height falls, terrain driven circulations, and weak diffluence aloft will combine for widespread thunderstorm development Thursday afternoon/evening. RAP forecast soundings show 500 to 750 J/kg MLCAPE and 1000-1300 J/kg MUCAPE at KGJT which is well above the 90th percentile and near the all time maximum for mid-September in GJT based on SPC sounding climatology. This abnormally unstable airmass combined with moderate shear will result in an environment capable of a few weak supercells producing isolated large hail and severe wind gusts across eastern Utah, the Four Corners region, much of Colorado, and southern Wyoming. ...Bentley.. 09/10/2025 $$ = = = 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) .