Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Mar 15 2023 17:02:32 ACUS02 KWNS 151702 SWODY2 SPC AC 151700 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1200 PM CDT Wed Mar 15 2023 Valid 161200Z - 171200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF NORTHEAST TEXAS...SOUTHERN OKLAHOMA AND INTO THE ARKLATEX... ....SUMMARY... Scattered severe thunderstorms capable of producing large hail, damaging winds, and a few tornadoes appear likely Thursday afternoon and evening across parts of the southern Plains. Some of the hail could be very large over south-central Oklahoma and north-central Texas. ....Synopsis... A low-amplitude shortwave trough will move quickly east across the South Plains on Thursday, into the Ozarks during the evening and to the OH Valley by 12Z Friday. This wave will provide height falls over a broad region with midlevel winds increasing to 70 kt, enhancing shear. A northern-stream trough will also move toward the Upper MS Valley, with a tight midlevel temperature gradient and rapid cooling expected. At the surface, low pressure will exist over southern KS Thursday morning, with a cold front moving rapidly southeast to a Green Bay WI to Dallas TX line by 00Z Friday. A warm front will extend southeastward from the KS low across eastern OK and TX to start the day, moving north across the Arklatex by 00Z and into southwest AR by evening. Strengthening southerly winds will aid moisture return across the warm sector, with 60 F dewpoints meeting the front over southern OK, and mid 60s F over much of east/northeast TX and perhaps to the Arklatex by around 00Z. Surface pressures will increase ahead of the cold front over the Southern Plains into the lower MS Valley through the period as the cold air undercuts the warm sector and primary low rapidly deepens over the upper Great Lakes. Even so, the combination of destabilization over the southern Plains, strengthening shear and lift along the cold and warm fronts will likely lead to swaths of severe storms beginning Thursday afternoon, mainly from southern OK into northeast TX and toward the Arklatex and Sabine River. ....OK and TX Late afternoon through early evening... As the cold front pushes south, storms are expected to form by 20Z over central and southern OK, with additional activity building south and translating east across much of North TX through 00Z. Storms forming near the low and riding along the warm front into southeast OK will have tornado potential as given effective SRH over 300 m2/s2. Storms farther southwest toward the Red River and into TX may produce very large hail due to better lapse rates and instability. With time, the front will undercut the activity, with wind damage along with elevated hail expected. Farther south along the front into central/eastern TX, the front will continue to push rapidly south overnight, with increasing storm coverage. Ample instability will interact with the front, with parallel deep-layer shear vectors and weakening winds in the low levels. Hail appears to be the main threat as the storms become undercut by the cold air, but a narrow zone of damaging wind potential could materialize should storms propagate fast enough to keep up with the front. The cells over southern OK and North TX prior to 00Z in particularly may produce damaging hail and a tornado or two before the front undercuts the activity. Any cells or bows that can propagate with a strong eastward component may reside along the boundary longer, enhancing both severe wind and tornado threat. Another area of potential will be over northeast TX ahead of the cold front during the afternoon and evening. Initially, these storms will be elevated as they move into AR, beneath a 50+ kt low-level jet. As the warmer air moves into this region, a few supercells will be possible with tornado, hail and wind potential. Instability is forecast to be limited farther east, but strong shear may allow a few severe storms to produce damage into northern LA and southern AR. ....Lower MS Valley overnight... Height falls as well as increasing winds aloft will overspread the region despite the main wave passing well to the north. Winds around 850 mb will still be over 40 kt, veering to west/southwesterly. This will essentially parallel the cold front which will push into MS and central LA by 12Z Friday. Given the cool/dry air mass initially in place, temperatures will likely be limited to the 60s F from afternoon into the overnight. The moistening boundary layer will maintain warmth overnight, but MUCAPE values are forecast to be very low. Many models indicate zero SBCAPE north of about I-10. Nonetheless, strong lift along the front will result in showers and thunderstorms, and some of this activity could potentially produce strong wind gusts given flow magnitudes just off the surface. ...Jewell.. 03/15/2023 $$ = = = 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) .