Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 21 2023 07:25:35 ACUS03 KWNS 210725 SWODY3 SPC AC 210724 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Tue Mar 21 2023 Valid 231200Z - 241200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM TEXAS HILL COUNTRY ACROSS NORTHWEST/NORTH-CENTRAL TEXAS INTO SOUTHEAST OKLAHOMA... ....SUMMARY... Thunderstorms capable of hail, some very large, and damaging gusts are possible Thursday afternoon through Friday morning across the southern Plains. ....Synopsis... The upper pattern early Thursday is forecast to consist of a western CONUS trough and subtropical ridging centered over the Gulf of Mexico. Enhanced mid-level westerly/southwesterly flow will persist between these two features, extending from northern Mexico into the Great Lakes region. A pair of shortwave troughs will be embedded within the belt of stronger flow, one initially near the Mid MO Valley and the other across southern AZ/northern Mexico. Both shortwaves are expected to progress northeastward, with the second shortwave moving through the southern High Plains during the afternoon/evening, reaching KS/OK by early Friday morning. The surface pattern Thursday morning will likely feature a low over southern MI, with a cold front extending southwestward to another low over northwest TX. The northern portion of the cold front will remain progressive, moving eastward across the OH Valley. The southern portion of the front (from northwest TX across OK) will only make modest eastward/southeastward progress throughout the day, as another low develops over west TX. This second low is then expected to push northeastward along the front from Thursday evening into Friday, moving from the Permian Basin into southeast OK. At it does, an associated dryline will move eastward across southwest and central TX. ....Southern Plains... Low to mid 60s dewpoints are expected be in place along the front early Thursday morning, likely increasing into the mid/upper 60s by the late afternoon. This increasing low-level moisture coupled with modest daytime heating should destabilize the airmass south of the front by the late afternoon. Consequently, convergence along the front is expected to result in thunderstorm development, likely beginning over OK. Vertical shear will be strong, and the initial more cellular development may produce hail. However, the slow-moving front combined with the front-parallel orientation of the deep-layer vertical shear suggests numerous storms and messy storm mode. This could limit the overall severe potential across much of OK. Farther south, thunderstorm development is anticipated ahead of the deepening surface low expected to move into northwest TX during the late afternoon/early evening. A more cross-boundary vertical shear vector is anticipated here, supporting a greater potential for supercells for at least a few hours. Very large hail is possible with these storms as well as damaging gusts. As the low and associated front continue eastward, storm coverage should increase southward across the TX Hill Country/Edwards Plateau. Hail and damaging gusts are possible with this line of storms as it moves eastward toward the I-35 corridor early Friday morning. ...Mosier.. 03/21/2023 $$ = = = 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) .