Subj : DAY1SVR: Day 1 Convective To : All From : Mike Powell Date : Fri Sep 12 2025 09:25:56 ACUS01 KWNS 121244 SWODY1 SPC AC 121243 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0743 AM CDT Fri Sep 12 2025 Valid 121300Z - 131200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA EAST ACROSS MUCH OF THE DAKOTAS...AND IN THE FOUR CORNERS REGION... ....SUMMARY... A few storms capable of isolated severe wind gusts and hail are possible across the Four Corners region, and from eastern Montana into the Dakotas. ....Synopsis... An upper trough will remain over the Intermountain West, making slow eastward progress through tonight. An embedded disturbance is forecast to move from CO into the Dakotas late in the day, while a midlevel jet rounds the base of the trough across AZ overnight. Gradual height falls will occur across the length of High Plains primarily overnight as the upper-level ridge to the east gradually weakens. ....Eastern MT into the Dakotas... Thunderstorm development/intensification is expected across MT/WY east of a mid-level trough axis, where cool mid-level temperatures and surface dew points in the 50s will lead to MLCAPE in the 500 - locally 1000 J/kg range. Southwesterly deep-layer shear averaging 20-35 kts will be favorable for isolated storms with hail potential. As storms move/develop farther east across eastern MT/western ND/northwest SD towards evening, greater instability (MLCAPE on the order of 2000 J/kg) should result in a severe hail and wind risk with isolated stronger storms within a similarly-sheared environment. Although the low-level jet should be weaker in this area tonight, lingering instability across the western Dakotas suggests some continued severe risk, primarily for strong/damaging gusts, into the overnight hours. ....Four Corners Region... Scattered to numerous thunderstorms are expected to develop/intensify today from eastern AZ/southeast UT across western portions of NM/CO, within a moist plume on the eastern periphery of the mid-level trough. Cool mid-level temperatures will contribute to modest MLCAPE, with locally higher values (above 1000 J/kg) over southeastern AZ. A predominantly cellular or cluster mode is expected, with isolated stronger storms capable of marginally severe wind and hail. Storms should persist into the evening over western NM/CO, with a few stronger storms remaining possible. ...Bunting/Broyles.. 09/12/2025 $$ --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1) .