Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Nov 26 2023 20:00:17 ACUS01 KWNS 262000 SWODY1 SPC AC 261958 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0158 PM CST Sun Nov 26 2023 Valid 262000Z - 271200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Severe thunderstorms are not expected. ....Discussion... Primary change has been to trim the northwest extent of the thunder area in the Southeast based on latest obs. Low probability for a transient supercell remains evident in the 22-02Z time frame, mainly along the west-central FL coast near the quasi-stationary front draped from 30 SW OCF to around DAB. To the south of this front, the 18Z RAP remains on the aggressive end of guidance, suggesting the intrusion of MLCAPE in excess of 1000 J/kg from the northeast Gulf. Convection within the low-level warm theta-e advection regime preceding this potential buoyancy intrusion is ongoing west-southwest of Tampa Bay. This activity should shift east-northeast over the next few hours within a wind profile marginally conducive to low-level updraft rotation. But bulk of 12Z HREF and NSSL-MPAS guidance and the 18Z HRRR are insistent that convection will weaken as it moves inland over the peninsula and generally subside after mid-evening. ...Grams.. 11/26/2023 ..PREV DISCUSSION... /ISSUED 1006 AM CST Sun Nov 26 2023/ ....Synopsis... Thunderstorm potential for the remainder of today/tonight will be focused around two compact coastal lows - one over the northeastern Gulf of Mexico and another migrating northeastward along the Mid-Atlantic/New England coast. ....Northeastern Gulf Coast/FL Big Bend region... Morning soundings sampled 50-60 knot mid-level flow along the FL Gulf coast, which should be supportive of organized convection given weak southeasterly low-level flow. However, recent lightning and radar trends suggest ongoing offshore convection within a relatively buoyant air mass is struggling to maintain intensity/organization. This is likely attributable to poor mid-level lapse rates (also sampled by morning soundings) and somewhat weak forcing for ascent. Ongoing precipitation across central/northern FL will likely inhibit the northward progression of higher quality low-level moisture (dewpoints >= 70 F), and may maintain a slight cold advection regime across northern FL for much of the day. Combined with the modest lapse-rate environment, this should modulate surface-based buoyancy values over land. Consequently, confidence remains low that any organized convection that can develop over the northeastern Gulf waters will maintain intensity upon landfall along the Big Bend coast. Trends will continue to be monitored through the afternoon as a low-end severe threat may materialize if coastal buoyancy exceeds current expectations. ....Mid-Atlantic/New England Coast... A few lightning flashes will be possible overnight as a warm advection regime associated with the coastal low overspreads the Mid-Atlantic/New England coast. Despite strong flow aloft, the elevated nature of any convection, combined with very modest buoyancy profiles, should preclude organized thunderstorms. $$ = = = 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) .