Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 29 2023 16:18:42 ACUS01 KWNS 291618 SWODY1 SPC AC 291617 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Fri Sep 29 2023 Valid 291630Z - 301200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER MIDWEST... ....SUMMARY... Isolated large hail and locally damaging winds will be possible across parts of the Upper Midwest between about 6 PM to 2 AM CDT. ....Northeast NE to east-central MN... Primary categorical change with this outlook is to reorient the spatial extent of the expected threat in the wake of this morning's storms amid above-average consistency in 12Z CAM guidance. Gradual mid-level height rises are expected across the region as a shortwave trough progresses northeast from the Upper Red River Valley across northern ON. Differential boundary-layer heating will reinforce the southwest to northeast baroclinic zone from northeast NE/southeast SD through east-central MN. A storm or two might develop along the southwest flank of this corridor in the early evening where MLCIN is minimized with a conditional threat of marginal severe wind gusts. The more probable scenario is for slightly elevated thunderstorm development to occur after sunset from southwest to east-central MN on the nose of a strengthening low-level jet. Low-level hodographs will favor updraft rotation with initial storms, but a decrease in winds with height along with some reduction in steep lapse rates owing to slow mid-level warming should temper hail magnitudes beyond golf ball size. The longevity of the isolated large hail threat should also be curtailed to around 3-4 hours as storm mode becomes dominated by clusters and instability/buoyancy wanes overnight. ...Grams/Bentley.. 09/29/2023 $$ = = = 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) .