Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 22 2023 12:51:07 ACUS01 KWNS 221251 SWODY1 SPC AC 221249 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Mon May 22 2023 Valid 221300Z - 231200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR THE TX PANHANDLE AND SOUTH PLAINS... ....SUMMARY... Severe thunderstorms are possible across portions of the southern High Plains this afternoon and evening. Large hail and damaging gusts will be the primary hazards with these storms. Additional strong to isolated severe thunderstorms are possible across portions of Montana, and parts of southern Alabama/Georgia into Florida. ....TX Panhandle/South Plains this afternoon/evening... A convectively enhanced midlevel trough over extreme southwest KS will drift only slowly east-southeastward through tonight, with modestly enhanced (25-30 kt) westerly midlevel flow on its southern flank (over the TX Panhandle). In the low levels, southerly low-level flow will advect boundary-layer dewpoints in the low 60s northward from southwest TX to the TX Panhandle by this afternoon. As afternoon surface temperatures warm into the low-mid 80s beneath midlevel lapse rates of 7.5-8 C/km, MLCAPE will increase to 1500-2000 J/kg and convective inhibition will be largely removed. This will allow scattered thunderstorm development by mid afternoon along and east of the lee trough, from the TX Panhandle into the South Plains. Deep-layer vertical shear will be on the lower margins for supercells, with relatively straight hodographs. Thus, a mix of transient supercells and multicell clusters can be expected, with a tendency for upscale growth along consolidating outflows by this evening, as low-level warm advection increases. The modest wind profiles and steep lapse rates will favor occasional severe outflow gusts of 60-70 mph and isolated large hail up to 1.75 inches in diameter as the main severe threats. ....Central MT this afternoon/evening... A cold front will move slowly eastward into western and central MT, as an associated midlevel shortwave trough rotates northeastward from northeast OR/eastern WA to western MT by this afternoon. Though low-level moisture is limited (boundary-layer dewpoints in the mid-upper 40s), surface heating and deep mixing ahead of the front will result in steep low-level lapse rates and MLCAPE of 500-1000 J/kg with minimal convective inhibition. Thunderstorms should first form by early afternoon over the high terrain of southwest MT, and then spread northeastward through the afternoon/evening into central MT. The stronger midlevel flow and deep layer shear will be along and west of the front, so primarily multicell clusters are expected with the potential to produce isolated large hail of 1 to 1.5 inches in diameter and strong-severe outflow gusts of 50-65 mph. ....Northeast Gulf coast into FL this afternoon... A weak midlevel trough will persist over MS/AL today, while a backdoor cold front drifts slowly southward near the borders of north FL and GA/AL. This surface front, along with colliding outflows and sea breezes across the interior FL peninsula, will focus thunderstorm development this afternoon. Midlevel lapse rates will not be steep, but there will be some modest enhancement to vertical shear will easterly low-level flow beneath westerly midlevel flow. The net result will be the potential for semi-organized cells/clusters to produce isolated strong-severe outflow gusts of 50-60 mph. ...Thompson/Broyles.. 05/22/2023 $$ = = = 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) .