Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Dec 04 2022 17:17:43 ACUS02 KWNS 041717 SWODY2 SPC AC 041715 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CST Sun Dec 04 2022 Valid 051200Z - 061200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk for severe thunderstorms appears negligible across the U.S., Monday through Monday night. ....Synopsis... Higher latitude blocking, including one prominent mid-level ridge across the Greenland vicinity, likely will be maintained through this period and beyond. To the southwest of this ridge, a broad mid-level low continues to evolve across much of Canada and the northern tier of the U.S. (to the east of the Rockies), with some retrogression of its deep center to the west-northwest of Hudson Bay forecast through Monday/Monday night. As this occurs, models indicate that cold surface ridging will build and begin to nose southward to the lee of the Canadian Rockies, preceded by a more modest cold intrusion across much of the Upper Midwest, upper Mississippi Valley and northern into central Great Plains by 12Z Tuesday. A prior cold front is now in the process of stalling across the south Atlantic and Gulf Coast vicinity, and is forecast to weaken/ retreat northward beneath a modestly amplified belt of westerlies emanating from the mid-latitude eastern Pacific. By late Monday into Monday night, it appears that this will include building mid-level ridging across the Southeast (to the north of a prominent subtropical high centered near the Yucatan Peninsula) and digging, positively tilted large-scale troughing near and to the west of California and Baja California. Downstream of this troughing, a plume of lower/mid-tropospheric moist return flow, which has developed off the lower latitude eastern Pacific, may become suppressed south of the Southwestern international border vicinity by 12Z Monday. But mid-level moisture return will continue around the western/northwestern periphery of the downstream ridging, across Texas and the lower Mississippi Valley into the western slopes of the southern Appalachians and surrounding Southeast. At the same time, it appears that modest ongoing low-level moisture return, emanating from the western Gulf of Mexico, will gradually spread from southern/eastern Texas through much of the Mid South and Tennessee Valley vicinity, while also increasing off the northwestern Gulf into the central Gulf Coast states. ....Gulf Coast/Southeast... Warming mid-level temperatures probably will cap weak surface-based (or near surface-based) destabilization across much of the Gulf coastal plain Monday through Monday night. However, despite generally weak mid-level lapse rates, elevated moisture return farther north may contribute to weak destabilization and convection rooted within a developing persistent lower/mid tropospheric warm advection regime, across the Mid South into southern Appalachians vicinity. This may include occasional embedded thunderstorm development, aided by mid/upper provided by weak perturbations migrating around the periphery of the subtropical ridge. ....Northern California vicinity... Weak instability beneath the mid-level cold core of a remnant digging cyclonic circulation will contribute to the risk for convection occasionally capable of producing lightning, from near coastal areas into the Sierra Nevada. ...Kerr.. 12/04/2022 $$ = = = 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) .