Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jan 24 2023 19:52:53 ACUS01 KWNS 241952 SWODY1 SPC AC 241951 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0151 PM CST Tue Jan 24 2023 Valid 242000Z - 251200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE UPPER TEXAS COAST...AND EXTENDING EAST ALONG THE NORTHERN GULF COAST... ....SUMMARY... Damaging winds and a few tornadoes remain possible today across the upper Texas Coast, and extending eastward tonight across coastal areas of Louisiana, Mississippi, Alabama, and the western Florida Panhandle. ....Upper TX Coast eastward along the northern Gulf Coast... A focused area of tornado potential currently exists near the Houston area near the warm front and surface low. Extreme pressure falls have been noted over the area ahead of a line of storms with 2hr falls around 8 mb. Shear remains quite strong with effective SRH over 500 m2/s2. In addition, surface/boundary-layer winds are intense which will enhance storm relative inflow. As such, a tornado and damaging wind risk may increase over the next few hours. A strong tornado is possible conditional on storm mode and access to the warm side of the warm front. Later this evening and overnight, the warm front will move onshore across LA mainly after 00Z, and into southern AL/FL Panhandle after 06Z. Shear will remain strong and favorable for supercells with tornado risk. ...Jewell.. 01/24/2023 ..PREV DISCUSSION... /ISSUED 0954 AM CST Tue Jan 24 2023/ ....Synopsis... Surface low intensification should continue along the western Gulf Coast today as a strengthening mid-level trough overspreads the lower MS Valley. Though a relatively stable low-level airmass remains in place inland, a moist and (surface-based) buoyant airmass resides immediately offshore of the southern TX coastline. This airmass should be drawn roughly 50-150 nm onshore into TX ahead of the surface low through the afternoon, and later tonight along the central Gulf Coast. An intense low-level jet will also overspread the Gulf Coast shoreline ahead of the surface low, with impressive vertical shear profiles and marginal (but potentially adequate) buoyancy promoting severe thunderstorm development through the period. ....Texas Shoreline this Afternoon... Elevated convection is ongoing across southeast Texas within an elevated warm-air advection regime ahead of the surface low. With time, continued low-level moisture advection and (limited) diurnal heating will encourage gradual surface-based destabilization immediately ahead of the surface low for the TX counties along the shore. As such, elevated thunderstorms in these counties may gradually become surface-based. The 50-70 kt low-level jet, overspread by 80-100 kts of west-southwesterly 500 mb flow will contribute to very large, highly curved hodographs. Guidance suggests that near 70 F/upper 60s F surface temperatures/dewpoints and resultant 500 J/kg thin SBCAPE is all that is needed to draw at least 300-500 m2/s2 of SRH into the effective inflow-bearing layer. Storms that root into the boundary layer may acquire strong rotation. Given the very impressive low-level shear, any tornado that can form (whether brief or sustained) could be strong. An instance or two of large hail is also possible given the presence of near 7 C/km mid-level lapse rates (per 15Z mesoanalysis). ....Lower Mississippi Valley Tonight... As the surface low approaches the lower MS Valley this evening into tonight, a line of semi-discrete but strong thunderstorms should move across southern LA into southern MS and AL, immediately preceded by a marginal but potentially surface-based airmass. Though questions remain how far inland the most buoyant air parcels will advect, at least some potential exists for mid to upper 60s F dewpoints to overspread coastal counties. Should this occur, enough surface-based instability will be present (i.e. around 500 J/kg SBCAPE) to support a severe gust/tornado threat given impressive vertical shear profiles (similar to TX during the day). Given the presence of very strong low-level shear, at least a couple of strong tornadoes are possible. $$ = = = 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) .