Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jan 20 2023 05:22:04 ACUS02 KWNS 200521 SWODY2 SPC AC 200520 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1120 PM CST Thu Jan 19 2023 Valid 211200Z - 221200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. Saturday through Saturday night. ....Synopsis... Models indicate that large-scale mid-level troughing, initially east of the northern U.S. Atlantic coast, and associated lower/mid-tropospheric cyclone to the southeast of the Canadian Maritimes, will progress away from the Atlantic Seaboard Saturday through Saturday night. In its wake, generally dry and/or cold and stable conditions will prevail across a large portion of the U.S., to the north of a prominent frontal zone initially stalling across the Florida Peninsula and northern Gulf of Mexico. Upstream, mid-level ridging is forecast build offshore of the southern U.S Pacific coast into coastal southeastern Alaska, with an embedded high becoming a bit more prominent through at least this period across the southern mid-latitude eastern Pacific. To the east of this evolving regime, model output continues to exhibit considerable spread concerning short wave developments within westerly/northwesterly flow inland the Pacific coast into areas east of the Mississippi Valley. However, in general, one significant short wave impulse is forecast to shift east of the southern Rockies, as a stronger perturbation digs inland of the British Columbia/Pacific Northwest coast. Another perturbation, splitting off a branch of westerlies to the north, and the lead impulse may consolidate into larger-scale troughing over the lower Missouri Valley/southern Great Plains vicinity, gradually interacting with a branch of westerlies emanating from the subtropical eastern Pacific by late Saturday night. However, models indicate that associated surface cyclogenesis will be limited to a modest wave along the front across the northwestern Gulf of Mexico into southern Mississippi/Alabama coastal areas, after an initial weak lee cyclone over the Texas Panhandle vicinity weakens earlier in the period. ....Gulf Coast states... It does appear that an evolving south/southwesterly return flow will become sufficiently warm and moist to contribute to weak destabilization and a risk for thunderstorm activity, above/to the north of the frontal zone over the northern Gulf of Mexico, and inland of coastal areas. In response to the developing frontal wave, guidance suggests that the frontal zone may advance northeastward toward coastal areas, between the far southeastern Louisiana parishes and the western Florida Panhandle, perhaps accompanied by weak to modest boundary-layer destabilization across at least portions of the coastal waters. Coupled with at least some strengthening of lower/mid tropospheric wind fields, it might not be out of the question that the environment could become conducive to organized convection, including supercell structures. However, the risk for severe weather across and inland of the coast still appears negligible (less than 5 percent probabilities) at this time. ....Pacific Northwest... A mid-level cold core, including 500 mb temperatures near or below -30C, may be accompanied by sufficient destabilization to support low topped convection capable of producing lightning as it overspreads the Puget Sound and northern Washington Cascades vicinity Saturday afternoon. ...Kerr.. 01/20/2023 $$ = = = 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) .