Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Feb 06 2023 08:41:39 ACUS03 KWNS 060841 SWODY3 SPC AC 060840 Day 3 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0240 AM CST Mon Feb 06 2023 Valid 081200Z - 091200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MISSISSIPPI VALLEY AND TENNESSEE VALLEY... CORRECTED FOR TYPO ....SUMMARY... At least isolated severe thunderstorms are expected Wednesday and Wednesday night across the Lower Mississippi Valley and Tennessee Valley. ....ArkLaTex to Tennessee Valley including LA/AR/MS/AL/TN... Severe-weather potential is expected to increase into Wednesday across the region. This will be as a shortwave trough/polar jet spread northeastward from the south-central Plains/Ozarks toward the Midwest and interface with an increasingly moist air mass across the Lower Mississippi Valley/Tennessee Valley. However, numerical guidance timing/spatial variability and the likelihood of early day convection, as well as modest overall destabilization, cast uncertainty regarding the potential and placement of somewhat higher severe probabilities (such as a Slight Risk) at this time. Recent NAM runs continue to be much more east-northeastward progressive as compared to recent ECMWF/GFS guidance. Early day cloud cover and scattered thunderstorms will likely be semi-persistent factors ahead of the cold front on Wednesday, although most global guidance has trended slightly more unstable with respect to the warm/moist sector over the prior 24-36 hr of guidance runs. Regardless, currently thinking is the warm sector will at least modestly destabilize Wednesday across portions of Louisiana into Arkansas/Mississippi. At least an isolated severe-weather potential should increase accordingly, including damaging wind/tornado risks. This severe potential should reach portions of Alabama/Tennessee Wednesday night. An upgrade to a categorical Slight Risk could be warranted for portions of the region into the Day 2 time frame as forecast details become clearer. ....Lower Ohio Valley/Midwest... Steady northeastward ejection of the shortwave trough and related deepening phase of the northeastward-advancing surface cyclone from the Ozarks to the Midwest could influence a strongly forced low-topped convective line across the region Wednesday night, even in the presence of minimal instability with northward extent. Given a pronounced strengthening of deep-layer winds, along with steepening lapse rates atop residual but eroding boundary layer stability, at least low wind-related severe probabilities may be warranted in future outlooks, even with thermodynamic uncertainties/potential limitations. ...Guyer.. 02/06/2023 $$ = = = 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) .