Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Dec 05 2023 09:28:33 ACUS48 KWNS 050928 SWOD48 SPC AC 050926 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0326 AM CST Tue Dec 05 2023 Valid 081200Z - 131200Z ....DISCUSSION... ....Ozarks/East TX to the Lower OH Valley/Deep South... The amplifying shortwave trough in the Great Basin vicinity at the start of D4 should become highly amplified over the central states and roughly centered across much of the MS Valley near 12Z/Sun. This scenario is widely supported by the 00Z ECMWF/GEFS ensemble means and deterministic ECMWF/UKMET/CMC runs. Poleward moisture transport from the western Gulf will displace an initially modified CP air mass with low-level warm theta-e advection becoming pronounced on D4/Fri night. This should result in mainly elevated thunderstorms within the strengthening warm conveyor near the developing surface cyclone in the Ozarks vicinity. A low-probability severe threat is apparent in this region south-southwest towards the Ark-La-Tex. Greater severe-weather potential should develop on D5/Sat during the day as mid to upper-level southwesterlies strengthen across the warm sector and instability is boosted by diurnal surface heating, centered on east TX towards the Ark-La-Miss. Convection will likely become widespread by afternoon. The potential for extensive overturning lowers confidence in the degree of north/east extent of the severe threat away from the highlighted 15 percent area. As such, a broad low-probability severe threat should be implied to the north/east from the Lower OH Valley to the Deep South. ....Southeast to Mid-Atlantic States... Potential exists for robust cyclogenesis to peak in the late D5 to D6 time frame on Sun across parts of the Midwest to Great Lakes. The 00Z deterministic ECMWF is particularly intense as the highly amplified upper trough across the MS Valley becomes negatively tilted over the East on D6/Sun. However, ensemble spread within the ECMWF/GEFS appears quite large regarding synoptic details, and this is coupled with a high likelihood of a thermodynamically limited warm sector given weak mid-level lapse rates and negligible to meager buoyancy. But with at least conditional potential for extreme low-level wind fields to potentially overlap upper 50s to mid 60s surface dew points, low severe probabilities appear warranted. ...Grams.. 12/05/2023 = = = 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) .