Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri May 19 2023 05:48:45 ACUS02 KWNS 190548 SWODY2 SPC AC 190546 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Fri May 19 2023 Valid 201200Z - 211200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE SOUTHEAST...AND FROM THE EDWARDS PLATEAU INTO THE RIO GRANDE VALLEY IN TEXAS.... ....SUMMARY... Isolated severe thunderstorms are possible Saturday across much of the Southeast, and from the Edwards Plateau into the Rio Grande Valley in Texas. ....Synopsis... Primary shortwave trough is expected to be over Lower MI early Saturday morning, with another weaker shortwave farther west over the Lower MO Valley. The primary shortwave is forecast eastward through southwestern Ontario before turning more northeastward as it moves over the Lower Great Lakes and St. Lawrence Valley. Secondary shortwave will likely progress eastward/southeastward across central/southern MO and into TN Valley. At the surface, an occluded low associated with the primary shortwave will likely begin the period over southwestern Ontario before then moving northeastward through eastern Ontario and southern Quebec. An expansive cold front will extend southwestward from this low, stretching through the Upper OH Valley through the Mid-South and into South TX early Saturday morning. This front is expected to progress eastward/southeastward through the day, fostering thunderstorm development from the Northeast through the Mid-Atlantic and Southeast states to the TX Coastal Plain. ....Southeast... A moist air mass, characterized by dewpoints in the upper 60s to low 70s, is expected to be in place across much of the Southeast ahead of the approaching cold front. Despite relatively poor mid-level lapse rates, this moist air mass is expected to destabilize as filtered daytime heating pushes temperatures into the 80s. Convergence along the front will modest, but thunderstorms are still expected to develop given the lack of convective inhibition. Moderate afternoon buoyancy is anticipated, with guidance suggesting MLCAPE around 2000 J/kg. Additionally, a belt of moderate mid/upper-level flow will stretch across the region, northwesterly flow gradually increasing in strength above 700mb. This shear could support a few more organized storm structures capable of damaging gusts and/or hail. Highest thunderstorm coverage is expected over the central MS/AL border vicinity, and higher severe probabilities may be needed in this area in later outlooks. Uncertainty regarding the location of any early morning showers and thunderstorms (and resulting cloud cover) precludes higher probabilities with this outlook. ....Edwards Plateau into the Rio Grande Valley... A thunderstorm cluster may be ongoing over the TX Hill Country at the beginning of the period, and some severe may be possible if it continues southward into moist and unstable air mass over South TX/RGV during late morning/early afternoon. Even if this cluster does not survive into the region, afternoon thunderstorm development along its outflow is possible. Some potential also exists for development over the higher terrain of Mexico, with the resulting cells then moving across the border. ...Mosier.. 05/19/2023 $$ = = = 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) .