Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 14 2025 12:36:41 ACUS01 KWNS 141236 SWODY1 SPC AC 141234 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0734 AM CDT Thu Aug 14 2025 Valid 141300Z - 151200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ....SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts may occur this afternoon into tonight across parts of the northern/central Plains and upper Mississippi Valley. ....Northern/Central Plains into the Upper Mississippi Valley... Ongoing elevated thunderstorms across parts of eastern SD this morning are occurring in association with a low-amplitude shortwave trough and related low-level warm advection. This activity has remained sub-severe through much of the early morning hours, but it could still pose an isolated hail threat in the short term given weak MUCAPE and sufficient deep-layer shear. It remains unclear whether additional thunderstorm development will occur later this afternoon across parts of southern MN and vicinity as the shortwave trough continues eastward across the upper MS Valley. The airmass across this area will gradually destabilize through the day, but capping may tend to inhibit additional development. Still, a conditional threat for isolated severe hail/wind exists if robust thunderstorms can initiate, so have maintained the Marginal Risk across southern MN for this possibility. Thunderstorms across southern Manitoba this morning are expected to generally remain along/north of the international border as they continue eastward into western Ontario. A fairly strong mid/upper-level trough will progress eastward today across Saskatchewan/Manitoba, with the southern fringe of this perturbation glancing the northern Plains later today. Enhanced westerly mid-level flow will overspread ND and northern MN late this afternoon though tonight, while a surface cold front advances east-southeastward across the northern Plains through the period. Low-level moisture will continue to stream northward ahead of the front, with evapotranspiration also aiding surface dewpoints potentially reaching into the upper 60s to perhaps low 70s by early evening. Ample daytime heating and steep lapse rates aloft will aid in the development of at least 2500-3500 J/kg of MLCAPE by late afternoon. The primary uncertainty regarding convective development along the front is a capped 850-700 mb layer and weak forcing with southward extent across the northern Plains, as the primary upper trough will remain across Canada through the period. Even so, low-level convergence along the front may become sufficient for cells to initiate by early evening, mainly across parts of eastern ND into northwest MN where MLCIN should be weakest. Any convection which can be sustained could pose a threat for large to isolated very large hail given a favorable thermodynamic and kinematic environment. Some potential for upscale growth into clusters along the front remains apparent this evening into the early overnight hours, with greater severe wind threat. However, inhibition will quickly increase with eastward extent across MN as nocturnal cooling of the boundary layer occurs; so, the severe wind threat remains uncertain. Finally, scattered high-based thunderstorms should occur this afternoon and evening farther south across parts of the central High Plains. As this convection spreads eastward and encounters greater instability along/east of a surface lee trough, it may become capable of producing isolated severe gusts and perhaps marginally severe hail. The lack of stronger forcing aloft and modest deep-layer shear should temper the overall severe threat with southward extent. ...Gleason/Leitman.. 08/14/2025 $$ = = = 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) .