Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Nov 14 2024 10:02:28 ACUS48 KWNS 141002 SWOD48 SPC AC 141000 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Thu Nov 14 2024 Valid 171200Z - 221200Z ....DISCUSSION... ....D4/Sunday into D5/Monday... Extended-range guidance generally agrees that a mid/upper-level shortwave trough/closed low will move eastward across parts of the Southwest/northern Mexico through the day Sunday. This system will eject northeastward as a negatively tilted shortwave trough Sunday evening into Monday, accompanied by intense deep-layer flow fields and significant surface cyclogenesis. Meanwhile, recent guidance has trended toward somewhat richer low-level moisture return, with mid to upper 60s F dewpoints spreading into parts of southwest/central/north TX Sunday night into Monday, with at least low 60s F dewpoints into parts of OK/KS. Midlevel temperatures will remain relatively warm across the warm sector, but there is greater confidence in at least modest surface-based buoyancy (with MLCAPE of 500-1000 J/kg) developing across parts of west/central TX Sunday night, accompanied by an substantial increase in low-level and deep-layer shear. Isolated severe storm potential cannot be ruled out by late afternoon into early evening, but a notable increase in storm coverage is expected Sunday night. Extensive convection may result in a tendency toward a linear/QLCS mode, but intense deep-layer flow and increasing low-level shear will support a threat of severe wind gusts along with some tornado potential. A 15% area has been added for D4/Sunday, where intensifying flow is forecast to overlap sufficient instability amid as deep convection increases in coverage Sunday night. Some severe threat may persist from late D4/Sunday into at least early D5/Monday, as the shortwave and attendant surface low continue to eject northeastward. Uncertainty increases at this time range regarding the northern and eastern extent of the severe threat on D5/Monday, as richer low-level moisture potentially gets pinched off from the stronger ascent from the ejecting shortwave trough, and buoyancy becomes increasingly weak across the warm sector. Intense wind fields will support some severe-wind and tornado potential where convection can remain surface-based. There also may be some potential for renewed storm development Monday afternoon in the immediate vicinity of the ejecting shortwave and surface low across the central Plains (as suggested in the 14/00Z ECMWF), though this scenario remains quite uncertain. A small 15% area has been included for D5/Monday, as a continuation of the threat that begins late D4/Sunday. Depending on destabilization trends during the day on Monday, probabilities may eventually need to be expanded to the north and/or east of this area. ....D6/Tuesday - D8/Thursday... Some severe threat could linger on D6/Tuesday in the vicinity of the MS Valley, though model spread increases substantially at this range regarding the evolution of the upper-level pattern and occluding cyclone over the northern Plains/upper Midwest. Otherwise, Tropical Depression 19 has formed across the Caribbean, with the NHC forecast track suggesting this system may eventually approach some portion of the Gulf of Mexico. Uncertainty remains very high regarding any severe threat with this system into mid/late next week. ...Dean.. 11/14/2024 = = = 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) .