Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Oct 23 2023 19:56:01 ACUS01 KWNS 231955 SWODY1 SPC AC 231954 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Mon Oct 23 2023 Valid 232000Z - 241200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHWEST TEXAS AND THE UPPER MISSISSIPPI VALLEY... ....SUMMARY... A brief tornado is possible across a portion of southwest Texas this evening into the overnight. Isolated large hail will be possible late tonight across parts of the Upper Mississippi Valley. ....20Z Update... No changes have been made to either Marginal Risk area with this update. Ongoing thunderstorms over southern/eastern WI should weaken as they move eastward into a less unstable airmass. ...Gleason.. 10/23/2023 ..PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Oct 23 2023/ ....Texas Big Bend/Edwards Plateau... Low-level moisture will gradually increase across the region through tonight, while a cirrus canopy, related to the remnants of Norma, will tend to persist across a sizable part of Texas. Weak buoyancy is expected to develop and episodic bouts of isolated to scattered thunderstorms will focus from the Big Bend north-northeastward across the western Edwards Plateau, mainly this evening into the overnight. A strengthening low-level jet during this time frame will enlarge hodographs and may be sufficient for a transient supercell or two. But weak lapse rates through much of the vertical column will likely mitigate a threat beyond a low probability for a brief/weak tornado. ....Upper Mississippi Valley... Post-shortwave trough ridging and limited moisture should keep thunderstorm potential/coverage relatively low much of the afternoon and early evening. Elevated thunderstorms are expected to become more prevalent late this evening into the overnight to the north of a warm front, as a southwesterly low-level jet strengthens across Nebraska/Kansas/Iowa. Ample elevated buoyancy and steep mid-level lapse rates will favor potential for isolated large hail, spanning parts of southern Minnesota/possibly far northern Iowa eastward across Wisconsin toward the Lake Michigan vicinity. However, modest effective shear should tend to yield multicellular clustering, likely mitigating a more substantial/longer duration severe hail threat. $$ = = = 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) .