Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 02 2024 09:01:52 ACUS48 KWNS 020901 SWOD48 SPC AC 020900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Mon Sep 02 2024 Valid 051200Z - 101200Z ....DISCUSSION... Global models have come into a bit better agreement with each other, through late next week, with respect to their handling of the large-scale features. Day 4 (Thursday), the upper trough crossing central portions of Canada and the north-central U.S. is progged to continue digging southeastward -- reaching a roughly upper Mississippi Valley to Mid-Missouri Valley position by Friday morning. As this occurs, a corresponding eastward/southward advance of a surface cold front will occur, crossing the Upper Great Lakes/Upper Midwest and drifting as far south as the central Plains overnight. Preceding the front, limited low-level moisture is expected, with Gulf moisture remaining restricted to the southern-tier states. Thus, while a few strong/severe storms may evolve within a southern Upper Great Lakes to central Plains corridor, potential for a more widespread severe event appears limited at this time. Day 5 (Friday), a continued southeastward advance/amplification of the upper trough is anticipated, shifting across the Great Lakes and Midwest through the day, and with cyclonic flow surrounding the trough to encompass the entire eastern half of the country by Saturday morning. The associated cold front -- crossing the central U.S. through the day, is expected to reach a Lower Great Lakes to Lower Mississippi Valley to Texas position overnight. Meanwhile, the height falls associated with this trough into the southeastern U.S. may support frontal wave development along the remnant baroclinic zone likely to be lingering over the northern Gulf/Gulf Coast area. While still uncertain, this low may shift across the Southeast Friday, reaching the eastern Carolinas vicinity by Sunday morning. While it is not out of the question that -- with this front/low marking the northward extent of tropical low-level air, that low-end severe risk could evolve overnight. However, this scenario is uncertain, and would seem likely to remain limited in terms of significance. Day 6, some negative tilt of the upper trough is expected as it advances across the Midwest and Lower Great Lakes area, with models suggesting evolution into a closed low over the eastern Ontario vicinity with time. Meanwhile, the advancing cold front is progged to begin to overtake the remnant baroclinic zone and frontal wave, with the combined front to linger near -- and eventually move off -- the Atlantic Seaboard as the frontal low moves toward/into southern New England overnight. Again, some severe potential may manifest ahead of the consolidating surface front, but at this time, models suggest that destabilization will remain largely just offshore. By Sunday (Day 7) and continuing through the end of the period, model divergence increases -- with evolution/positioning of the deepening closed low over eastern NOAM, and -- as a result, the upstream flow pattern over the western half of the country. Overall severe risk would appear to be low overall however, with general ridging likely over the western half of the country. ...Goss.. 09/02/2024 = = = 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) .