Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 13 2024 08:16:29 ACUS03 KWNS 130816 SWODY3 SPC AC 130815 Day 3 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0315 AM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ....SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ....Midwest/Mid Mississippi Valley into the Southern/Central Plains... An initially weak upper trough should gradually consolidate and form into a closed low over the Upper Midwest on Thursday. A corresponding increase in westerly mid-level flow should occur across parts of the Midwest into the mid MS Valley. At the surface, a weak low should gradually occlude as it meanders over the Upper Midwest beneath the developing upper low. Although low-level convergence along an associated cold front extending southwestward from the surface low should remain fairly limited, a rather moist and unstable airmass should be in place ahead of the front by Thursday afternoon across parts of the Midwest and mid MS Valley. Early day convection should move eastward across these areas and weaken, with ample daytime heating in its wake. This heating combined with modestly steepened mid-level lapse rates will contribute to a strongly, and potentially extremely, unstable airmass. Increasing mid-level flow through the day should support strengthening deep-layer shear as well, with various NAM/GFS forecast soundings showing a veering wind profile with height through mid levels. This favorable thermodynamic and kinematic environment should support a threat for organized severe thunderstorms, including the potential for supercells and associated large hail threat. Sufficient low-level shear may also exist for a couple of tornadoes. However, the weak low-level convergence along the front leads to some uncertainty in overall thunderstorm coverage and placement. Regardless, a Slight Risk has been included where most guidance shows a convective QPF signal Thursday afternoon through late evening. Some chance exists for a bowing cluster to develop eastward across the Midwest, although confidence in this scenario remains fairly low. A Marginal Risk extends southwestward along the length of the weak front/wind shift into parts of the southern/central Plains. Although coverage of severe thunderstorms may remain more isolated across these regions, a well-mixed boundary layer could still support severe wind gusts with any high-based convection that can develop. ...Gleason.. 08/13/2024 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .