Subj : DAY1SVR: Day 1 Convective Outlook Corr 1 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 12 2025 20:15:23 ACUS01 KWNS 122014 SWODY1 SPC AC 122012 Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0312 PM CDT Tue Aug 12 2025 Valid 122000Z - 131200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GREAT LAKES REGION... CORRECTED FOR NDFD ....SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. ....20Z Update... Given the weak mid/upper-level flow, the potential for organized severe wind gusts appears very limited in southeast Arizona/southwest New Mexico. Steep low-level lapse rates may still support strong/gusty outflow however. Elsewhere only minor update the general thunderstorm area were made. See the previous discussion for additional details. ...Wendt.. 08/12/2025 ..PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Aug 12 2025/ ....Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ....Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. $$ = = = 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) .