Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 14 2025 17:33:56 ACUS02 KWNS 141733 SWODY2 SPC AC 141731 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Thu Aug 14 2025 Valid 151200Z - 161200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL WISCONSIN AND FAR EASTERN MINNESOTA... ....SUMMARY... Scattered severe storms are likely over parts of the northern Plains and Upper Mississippi Valley on Friday. ....Synopsis... A belt of stronger mid-level flow will be present across the northern Plains on Friday along the northern periphery of a broad mid-level ridge. Within this flow, a weak mid-level shortwave trough (perhaps amplified by Day1/Thursday convection across the central Rockies) will move across the northern Plains and into the Upper Midwest. This feature may be a focus for severe storms on Friday afternoon/evening. Another weak mid-level shortwave trough is forecast to traverse the central Rockies with associated ascent overspreading the central/northern High Plains. At the surface, weak lee troughing will be present across the central/northern High Plains with a front extending northeast across the northern Plains and into the Upper Midwest. ....Upper Midwest... Moderate to strong instability is forecast to develop south of a stationary front across the Upper Midwest Friday afternoon. The combination of ascent associated with a passing weak mid-level shortwave trough and strengthening isentropic ascent as the low-level jet strengthens, may provide ample lift for scattered thunderstorms Friday afternoon/evening. Several CAMS are in relatively good agreement for convective initiation across eastern Minnesota with the potential for upscale growth into a MCS across Wisconsin late Friday evening. Have introduced a Slight Risk across this region for an initial large hail threat, followed by an increasing severe wind threat if storms grow upscale. However, this area may need to be moved or enlarged in later outlooks due to the inherent lack of predictability within a low-amplitude pattern. Some of this unpredictability can be seen by relative outliers (HRRR and MPAS) which seems to stem from difference in convective evolution on Day 1/Thursday across the central Rockies and adjacent Plains tonight. ....Central/Northern High Plains into the northern Plains... Another weak mid-level shortwave trough is expected to traverse the Rockies on Friday and eventually overspread the northern Plains by Friday evening. Moderate to strong instability and moderate shear along the southern periphery of the stronger mid-level westerlies may result severe storms. Large hail would be possible in the initial, cellular stages (isolated severe wind across the NE Panhandle where a hot/well-mixed environment will be present), before an increasing severe wind threat may develop by later in the evening across South Dakota. If this MCS can maintain itself far enough east during the evening, the strengthening low-level jet across central and eastern South Dakota could maintain this MCS with some isolated severe wind threat into the early morning hours on Saturday across eastern South Dakota and perhaps far western Minnesota and northwest Iowa. ...Bentley.. 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) .