Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Oct 19 2023 04:52:00 ACUS01 KWNS 190451 SWODY1 SPC AC 190450 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Wed Oct 18 2023 Valid 191200Z - 201200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk of severe thunderstorms appears negligible across the U.S., today through tonight. ....Synopsis... In the wake of a prior cold intrusion, high moisture content air remains largely confined to areas along and south of a weakening surface front across the western Caribbean and Bahamas. Little substantive change appears likely today through tonight, although the front may redevelop west-northwestward toward the Florida Keys and Straits vicinity, as large-scale mid-level troughing amplifies east of the Mississippi Valley. Between prominent mid-level ridging centered over the subtropical western Atlantic and southwest of the Four Corners region, it appears that an initial mid-level low within the troughing will continue to weaken and become increasingly deformed across the lower Ohio Valley through lower Great Lakes region. This is forecast to occur as another strengthening perturbation digs within strong northwest flow around the crest of the Western ridging into the Eastern troughing. In response to these developments, a modest surface low may deepen a bit further across the Great Lakes region through Tennessee Valley, with a reinforcing surge of cooler air southeast of the Upper Midwest, into the Ohio Valley by early Friday. A weaker, and weakening, surge of cooler air may precede it across parts of the lower Ohio Valley into the western slopes of the Appalachians during the day. Near/offshore of the North Carolina coast, an area of low pressure may begin to form this evening through the overnight hours, beneath the leading edge of strengthening mid-level height falls. ....Lower Ohio/Tennessee Valleys... Forcing for ascent/cooling, within the exit region of the mid-level jet streak (increasing to 80-90 kt around 500 mb) associated with the digging short wave impulse, may contribute to a developing line of convection across parts of western Kentucky and Tennessee around/after 20/00Z. Although it appears that destabilization probably will become sufficient to support embedded thunderstorms as activity spreads toward the southern Appalachians, forecast soundings indicate that CAPE will be limited by only modest steepening of lapse rates and weak low-level moisture return from the Gulf of Mexico. Some small hail and gusty winds might not be out of the question, but the risk for severe storms still appears negligible. ....North Carolina Outer Banks vicinity... Although there is some spread evident in model output concerning the developing surface low through 12Z Friday, deeper boundary-layer moistening and associated destabilization supportive of vigorous convective development, if any, probably will remain confined offshore of the Outer Banks, near the Gulf Stream. ...Kerr/Thornton.. 10/19/2023 $$ = = = 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) .