Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Nov 17 2024 19:56:29 ACUS01 KWNS 171956 SWODY1 SPC AC 171955 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0155 PM CST Sun Nov 17 2024 Valid 172000Z - 181200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO FAR SOUTHWEST OKLAHOMA... ....SUMMARY... Scattered severe thunderstorms are expected to develop across parts of west/northwest Texas into southwest Oklahoma this evening and continuing through daybreak on Monday, posing a risk for severe gusts and a few tornadoes. ....20Z Update... ....Southern Plains... General forecast outlined in the previous discussion remain valid, with the cyclone currently entering northwest Mexico expected to continue eastward across northern Mexico before then ejecting more northeastward across the southern High Plains late tonight/early tomorrow morning. A strong mid-level jet will accompany this system, with 90-100 kt of 500-mb flow spreading across west TX and into southwest OK by early tomorrow. An intense low-level jet will develop ahead of this wave, with 60+ kt at 850-mb likely stretching from the TX Hill Country through central OK by 12Z Monday. Modest low-level moisture is still anticipated ahead of this system. Current surface analysis places the mid 60s dewpoints along and southeast of a line from PVJ in south-central OK to north of DRT in the Edwards Plateau. This area of greater low-level moisture will continue to advect northwestward throughout the day and evening, ahead of the approaching wave and associated surface low. Surface analysis also reveals a stationary boundary from END in north-central OK southwestward to just west of INK in the TX Trans Pecos. This boundary will likely provide the favored corridor for surface low progress late this evening and overnight. A strongly forced band of thunderstorm is still anticipated, beginning around 04-06Z in the Permian Basin vicinity, with this band then expected to rapidly move northeastward just ahead of the surface low, reaching central OK by 12Z. Intense low-level kinematic fields will precede this line, with strong flow associated with the mid-level jet as well. Resulting fast storm motion and downward momentum transfer supports the potential for severe gusts, despite the relatively modest thermodynamic environment. Highest probability for severe gusts is over northwest TX and far southwest OK from 09Z to 12Z Monday. A tornado risk will accompany this line as well, with the highest tornado probability in the same location and time as the greatest severe-wind threat. ...Mosier.. 11/17/2024 ..PREV DISCUSSION... /ISSUED 1030 AM CST Sun Nov 17 2024/ ....Synopsis... Water-vapor imagery this morning shows a potent mid-level low/trough over northwest Mexico with a downstream ridge centered over the eastern Gulf of Mexico. A mid-level vorticity maximum near the middle part of the Gulf of California will pivot east into Chihuahua by mid evening while the larger-scale trough becomes negatively tilted and moves northeastward into the southern High Plains. In the low levels, cyclogenesis over northern Mexico will gradually evolve today before the surface low deepens tonight reaching the northwest TX/western OK vicinity at the end of the period. Seasonably moist air via southeasterly flow from the western Gulf will advect into west TX before a Pacific front sweeps eastward across the Chihuahuan Desert and portions of the southern High Plains tonight. An attendant warm frontal zone will advance northward from north TX into OK late. ....Southern Great Plains... The 12 UTC Fort Worth, TX observed sounding showed an adequately moist/deep moist layer featuring a mean mixing ratio of 12.6 g/kg. The richer low-level moisture, featuring dewpoints in the mid-upper 60s as of late morning, is currently near the I-35 corridor from the Metroplex and areas south/southeast. Moisture advection will contribute to gradual destabilization through this evening across parts of west TX northeastward into southwest OK despite considerable cloud cover through the day. As an intense 100-kt 500-mb speed max moves from Chihuahua into west TX overnight, large-scale ascent will favor the development of scattered thunderstorms initially developing near the Permian Basin vicinity and becoming more widespread as very strong low-level warm advection attendant to an intensifying LLJ develops tonight. Model guidance indicates 250-1000 J/kg MLCAPE across the destabilizing warm sector. A forced band of storms will likely evolve tonight across west TX and rapidly move northeast in the area southeast of the surface low track. As the squall line matures, the propensity for severe gusts will probably increase despite relatively poor lapse given the intense flow expected to develop. It remains uncertain if cellular development will occur either ahead of the line or be loosely maintained in parts of the larger band of storms. Nonetheless, elongated and enlarged hodographs will favor a risk for scattered severe gusts and possibly a tornado risk, especially as the squall line encounters greater moisture from west-central TX northeastward into southwest OK late. $$ = = = 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) .