Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 22 2023 19:58:16 ACUS01 KWNS 221958 SWODY1 SPC AC 221956 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 22 2023 Valid 222000Z - 231200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF SOUTH TX...THE EASTERN GREAT BASIN TO NORTHERN ROCKIES...AND MI... ....SUMMARY... A brief tornado or two will remain possible through the rest of the afternoon across a portion of South Texas. Isolated severe wind gusts will be the primary threat later this afternoon across parts of the eastern Great Basin to the northern Rockies. Isolated severe hail will be possible across parts of Michigan early Wednesday. ....20Z Update... The 2% tornado probabilities in south TX have been trimmed to more closely align with an arc of convection to the east/northeast of TC Harold's center. While low-level shear/SRH will tend to gradually decrease with time as Harold weakens, transient low-topped supercells capable of a brief tornado or two will remain possible through the remainder of the afternoon to the north/northeast of Harold's track, as it continues to move west-northwestward. Elsewhere, no changes have been made to the Marginal Risk areas. See the previous discussion below for more information, and also see MCD 2025 for more information regarding the short-term threat from parts of UT into southwest WY. ...Dean.. 08/22/2023 ..PREV DISCUSSION... /ISSUED 1130 AM CDT Tue Aug 22 2023/ ....South TX... TC Harold near the Lower Texas Coastal Plain will move west-northwest and weaken across South TX into this evening. Potential for a brief tornado or two should linger to the west-northwest through north relative to the center circulation. Low-topped convection along the western extent of surface dew points at or above 76 F should remain coupled with adequate low-level SRH for a few more hours inland before the environment conducive to tornadoes diminishes spatially and in magnitude late this afternoon. ....Eastern Great Basin to the northern Rockies... Similar to yesterday, a moisture plume coincident with a belt of enhanced mid-level southerlies will support sporadic strong storms, focused on central to eastern UT and western WY. A few multicells and transitory/weak supercell structures should evolve this afternoon, mainly within a corridor where differential boundary-layer heating is most pronounced. While deep-layer shear will be sufficient for storm organization, moist profiles will render weak mid-level lapse rates, limiting the overall magnitude of destabilization and the severe wind threat. ....Upper Great Lakes... A repeat scenario of elevated thunderstorm development is expected during the early morning Wednesday shifted a bit farther east relative to this morning across parts of MI. With a stronger low-level jet overnight and deeper updrafts regenerating within the zone of isentropic ascent along the fringe of an EML expanding east from northern MN to western Upper MI, a cluster convective mode should largely dominate. This will probably marginalize the severe hail risk, while severe wind gusts appear unlikely given the stable boundary layer where storms are expected to occur. $$ = = = 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) .