Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Sep 26 2023 17:19:50 ACUS02 KWNS 261719 SWODY2 SPC AC 261718 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1218 PM CDT Tue Sep 26 2023 Valid 271200Z - 281200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE LOWER/MIDDLE OH VALLEY AND TN VALLEY... ....SUMMARY... Thunderstorms producing a few strong gusts or marginally severe hail will be possible across parts of the Ohio Valley into Middle Tennessee on Wednesday. ....Synopsis... A shortwave trough is forecast to move through the Pacific Northwest early Wednesday, continuing eastward through the northern Rockies and into MT during the afternoon and evening. Strong mid-level flow and cold mid-level temperatures will accompany this shortwave, with attendant large-scale forcing for ascent supporting isolated thunderstorm development from far northern Idaho through northern MT. Farther east, an upper low is forecast to move slowly eastward from northern IL into Lower MI. A low-amplitude shortwave through is expected to move through its western periphery across IA and into Mid MS Valley from Wednesday afternoon to early Thursday morning. A surface low will accompany the upper low, but its expected to be fairly weak and will likely fill throughout the day. A pair of modest, low-amplitude shortwave troughs are expected to move gradually southeastward across the southern High Plans and TX Hill Country/south TX, through the northeastern periphery of the upper ridging extending from the Baja Peninsula into the Four Corners. Isolated thunderstorms are expected downstream of these features during the afternoon and evening. ....Lower/Middle OH Valley and northern TN Valley... Previously mentioned surface low will likely be centered over east-central MO early Wednesday morning, before then gradually moving northeastward throughout the day. A warm front will likely arc eastward and then east-southeastward from this low, with a cold front extending back southwest. Showers and isolated thunderstorms will likely be ongoing Wednesday morning from near the surface low across IL and IN. Resulting cloud cover should sharpen the warm front throughout the day. Low-level moisture convergence near the warm front, as well as broad confluence across the warm sector across central KY, combined with modest heating and ample low-level moisture is expected to result in afternoon thunderstorm development. Buoyancy will be modest, but moderate mid-level flow could still support a few more organized storm structures. Given that these storms should be elevated, hail appears to be the most likely severe threat. Additional development appears possible later in the evening along the cold front across the Mid MS Valley. Strong heating is anticipated ahead of the front, with resultant steep low-level lapse rates contribute to some threat for isolated damaging gusts. ...Mosier.. 09/26/2023 $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .