Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Nov 18 2024 20:02:12 ACUS01 KWNS 182002 SWODY1 SPC AC 182000 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Mon Nov 18 2024 Valid 182000Z - 191200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN TEXAS AND LOUISIANA... ....SUMMARY... A risk for a couple of tornadoes and damaging winds is forecast into this evening from parts of east Texas into Louisiana and the central Plains this evening. ....20z Update... Across portions of eastern TX and western LA, scattered cloud breaks and low-level warm advection are supporting destabilization along and ahead of the main frontal precipitation band. As the front continues east, updrafts along the front should strengthen, with gradual storm development in the form of a QLCS. Ahead of the front, the latest forecast guidance also shows a couple of more discrete updrafts may eventually mature as temperatures warm. With strong deep-layer shear in place, storm organization into supercells capable of damaging gusts and a couple tornadoes is possible. Across portions of northeast LA and southern MS, buoyancy remains fairly limited. However, as the front/QLCS approaches, a few stronger updrafts may persist. Given the strong low-level shear, damaging gusts and a tornado or two will be possible into this evening, though the magnitude and coverage of the threat remain unclear. ....Central Plains and MO Valley... Widespread cloud cover and precipitation have been slow to erode ahead of the mid-level dryslot associated with the advancing mid-level trough. While buoyancy is expected to remain very weak (~300-500 J/kg of low-level MUCAPE), recent radar and satellite imagery show low-topped convective bands have emerged in a narrow area of cloud-breaks over south-central KS. Weak heating and dynamic cooling beneath the upper trough could support enough buoyancy for low-topped thunderstorms capable of isolated damaging gusts or a brief tornado through the remainder of this afternoon. ...Lyons.. 11/18/2024 ..PREV DISCUSSION... /ISSUED 1025 AM CST Mon Nov 18 2024/ ....East Texas into the Lower Mississippi Valley... Water-vapor imagery late this morning shows a negatively tilted mid-level trough over the southern High Plains rapidly moving northeast, and this feature will reach the Upper Midwest by early Tuesday morning. The southern portion of an ongoing convective line may continue to weaken across eastern/northeastern TX through the early afternoon. Models continue to suggest a risk for pre-squall line updrafts developing in the warm sector this afternoon from east TX into LA where MLCAPE may reach up to 500-1000 J/kg with daytime heating. Mid-level lapse rates will remain poor and the stronger forcing for ascent will gradually become displaced by late afternoon across this region. However, strong flow fields will support a risk for supercells with the stronger updrafts that develop. Uncertainty remains regarding the overall coverage (isolated) of potential supercells and their associated severe risk. Have left this portion of the outlook area unchanged. ....Central Plains/Ozarks into the Mid Missouri Valley... Morning surface analysis places a low over northwest OK with the zone of strongest pressure falls extending northeast into northeast KS where the low is forecast to track later today. A mid-level dryslot over the southern Great Plains will continue to shift northeastward into KS this afternoon and aid in some weak surface-based destabilization. In wake of morning showers/thunderstorms over KS, it remains possible sufficient weak destabilization occurs by mid-late afternoon immediately ahead of the low from central KS and quickly spreading northeastward into the MO Valley. Confidence is reserved regarding overall coverage of robust storm development due in part to extensive low cloud cover inhibiting destabilization, but it seems possible a couple of strong to severe thunderstorms may develop and yield an isolated risk for gusty winds and perhaps a tornado. $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .