Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jul 31 2024 01:02:01 ACUS01 KWNS 310101 SWODY1 SPC AC 310100 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Tue Jul 30 2024 Valid 310100Z - 311200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSOURI AND MID MISSISSIPPI VALLEY... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS... ....SUMMARY... Severe thunderstorms with severe gusts and isolated large hail will be possible tonight across parts of the northern Plains, and across the mid Missouri and mid Mississippi Valleys. Additional storms with isolated damaging wind gusts will be possible from parts of the lower Ohio Valley southeastward into the southern Appalachians. ....Northern Plains... On water vapor imagery, a subtle shortwave trough is moving eastward through the Dakotas, with multiple strong vorticity maxima evident in RAP analysis. At the surface, a dryline is located across the western Dakotas. Scattered thunderstorms are ongoing to the east of the dryline, within a moist airmass where surface dewpoints are in the lower to mid 70s F. This is contributing to strong instability, with the RAP showing MLCAPE over much of the central and eastern Dakotas in the 2500 to 4500 J/kg range. This will enable the stronger storms to persist this evening, with a severe threat likely continuing into the overnight period. Forecast sounding later this evening along and near the instability axis show moderate deep-layer shear and have steep mid-level lapse rates exceeding 8 C/km. This will likely support continued supercell development this evening into the overnight. Although a marginal tornado threat will be possible with the strongest of cells, large hail and severe wind gusts will be the primary threats. ....Mid Missouri and Mid Mississippi Valleys... An upper-level ridge is currently in place across the central U.S., with northwesterly mid-level flow located from the mid Missouri Valley southeastward into the mid Mississippi Valley. At the surface, a moist and unstable airmass is located from the Ozarks northwestward into central and eastern Nebraska. This airmass is forecast to remain over the central Plains and advect northward into the mid Mississippi Valley this evening into tonight. Thunderstorm development will be likely along the resultant instability gradient. As cells increase late this evening into the overnight period, cold pool organization will be possible from northeast Nebraska across Iowa and into western Illinois. The primary threats will be severe wind gusts and isolated large hail. There is still a chance for hailstones over 2 inches in diameter mainly within the generation zone of any organizing convective cluster or line, from northeast Nebraska into far western Iowa. ....Lower Ohio Valley to Southern Appalachians... The latest mosaic radar shows a linear MCS over western Kentucky, with additional scattered strong thunderstorms located over the southern Appalachians. The linear MCS is located along a sharp instability gradient, where the RAP is estimating MLCAPE in the 1000 to 2000 J/kg range. The instability, along with large-scale ascent associated with a subtle shortwave trough, will likely contribute to continued convective development this evening. Recent WSR-88D VWPs from western Kentucky to middle Tennessee have strong directional shear in the lowest 2 kilometers with northwest mid-level flow. This wind profile will continue to favor linear organization this evening into the early overnight. Any line segment that can remain intact should be accompanied by a wind-damage threat. ...Broyles.. 07/31/2024 $$ = = = 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) .