Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 21 2024 17:27:49 ACUS02 KWNS 211727 SWODY2 SPC AC 211726 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Wed Feb 21 2024 Valid 221200Z - 231200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk of severe thunderstorms still appears negligible across the U.S. for Thursday through Thursday night. ....Synopsis... Within the northern mid-latitudes, consolidating short wave perturbations of Arctic origins are forecast to dig southwest through south of the Hudson Bay vicinity through this period. It appears that this will contribute to larger-scale mid-level trough amplification across much of eastern North America, and be accompanied by a significant cold front crossing the north central Canadian/U.S. border (from the Great Plains into the upper Great Lakes) by Thursday night. As an initially more zonal belt of westerlies across the southern mid- into subtropical latitudes trends broadly cyclonic east of the Rockies into the Southeast, one embedded short wave currently emerging from the Southwest, is forecast to gradually dig from the Ozark Plateau/lower Ohio Valley vicinity through the Tennessee Valley/southern Appalachians Thursday through Thursday night. Downstream, initially amplified mid-level troughing over the southwestern Atlantic will continue to progress away from the southern Atlantic Seaboard. Upstream, models indicate that a lower/mid-tropospheric cyclone may gradually redevelop southward across the mid- into subtropical latitudes of the eastern Pacific, preceded by building mid-level ridging across California into the Great Basin. Northerly flow and subsidence in the wake of the Atlantic mid-level trough has contributed to relatively dry conditions across much of the Gulf Basin and Caribbean. Although some modification has been occurring across parts of the western Gulf of Mexico, and supporting a limited ongoing return flow of moisture across south/southeast Texas toward the Ozark Plateau vicinity, boundary-layer moistening over the western Gulf remains rather modest and shallow, beneath warm/dry layers in the lower/mid-troposphere advecting east of the Rockies/Mexican Plateau. ....Ozark Plateau into Ohio and Tennessee Valleys... Model forecast soundings generally suggest only gradual further boundary-layer moistening and deepening across the northwestern Gulf of Mexico through Thursday night, and little substantive improvement of the low-level moist return flow across the lower Mississippi into Ohio and Tennessee Valleys. Beneath warm-layers farther aloft, forecast soundings suggest that this will yield only weak CAPE where larger-scale ascent is able to overcome mid-level inhibition. And it appears that stronger forcing for ascent supportive of thunderstorm initiation may tend to remain focused above moist adiabatic to more stable near-surface lapse rates throughout the period. Scattered initial thunderstorm development across the lower Ohio Valley will probably be supported by forcing for ascent aided by low-level warm advection preceding slowly deepening surface troughing, well in advance of the Arctic front. However, various model output, including some convection allowing guidance, suggests that a weak developing cold front within this surface troughing could become a focus for an organizing line of thunderstorms across the lower Ohio through Tennessee Valleys late Thursday afternoon into Thursday night. While it might not be out of the question that some of this activity could be accompanied by small hail and gusty winds, with surface cyclogenesis and lower/mid-tropospheric wind fields forecast to remain seasonably modest to weak, the potential for severe weather still appears negligible. ...Kerr.. 02/21/2024 $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .