Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 12 2025 17:34:17 ACUS02 KWNS 121733 SWODY2 SPC AC 121732 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ....SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ....Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ....Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ...Mosier.. 08/12/2025 $$ = = = 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) .