Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Feb 23 2023 08:59:28 ACUS48 KWNS 230859 SWOD48 SPC AC 230858 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0258 AM CST Thu Feb 23 2023 Valid 261200Z - 031200Z ....DISCUSSION... For Sunday/D4, models continue to indicate the possibility of significant severe potential over parts of northwest TX, OK, and southern KS as a strong shortwave trough emerges into the southern High Plains Sunday/D4 afternoon. Low pressure is forecast to deepen through the period, moving from eastern CO into western KS during the day, and into northern MO by Monday/D5 morning. Model trends overall appear a bit faster with the wave, and farther south with the surface low. Wind fields will become very strong Sunday/D4 afternoon and night across the Plains as low-level moisture spreads north. Indications are that MLCAPE of 500 to perhaps 1000 J/kg will be possible ahead of the dryline/cold front, from northwest TX into southern KS as the low-level jet strengthens to 50 kt by late afternoon. Speeds around this level may exceed 70 kt by evening, while at the same time, strong veering with the cold front enhances convergence. The most likely scenario appears to be for a few supercells initially across western parts of the risk area, from the TX Panhandle and northwest TX into western OK, with large hail and tornado risk in proximity to steeper low-level lapse rates. A rapid transition to linear mode is expected as the system pushes east/northeast across OK and KS, with both damaging winds and QLCS tornado risk given 0-3 km shear over 50 kt and effective SRH over 300 m2/s2. Other severe storms along the cold front will be possible farther south into TX which is south of the stronger large-scale ascent. Still, the strong cold front and sufficient instability may counteract capping concerns to produce areas of damaging wind potential. Last, lack of instability will be the main factor across northern areas toward Kansas City, but a conditional severe risk may develop there as well should sufficient SBCAPE develop. On Monday/D5, the system is forecast to continue rapidly east across the OH Valley, with the low occluding as it moves toward Lower MI. MUCAPE values are only averaging 50-100 J/kg per latest model guidance, and this will mitigate severe potential. Given 50 kt winds just off the surface, a conditional risk of at least isolated damaging gusts may develop on Monday/D5, and model trends will continue to be monitored. For the Tuesday/D6 to Thursday/D8 time frame, models indicate another large trough developing over the West late in the period, with moisture return over the southern Plains and lower MS Valley Wednesday/D7 into Thursday/D8. This may setup another severe weather event from TX into the Southeast Thursday/D8 and beyond, but predictability is low. ...Jewell.. 02/23/2023 = = = 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) .