Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 20 2023 07:24:00 ACUS03 KWNS 200723 SWODY3 SPC AC 200723 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Wed Sep 20 2023 Valid 221200Z - 231200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL PLAINS... ....SUMMARY... Scattered strong to severe storms, capable of all severe hazards, are expected across portions of the central Plains on Friday. ....Synopsis... A pronounced mid-level trough will eject into the central and northern Plains on Friday, supporting surface cyclogenesis across the central High Plains and modest low-level moisture return across the central Plains. Cooler mid-level temperatures will overspread the low-level moisture axis with the ejection of the upper trough, destabilizing the warm sector and increasing synoptic-scale vertical ascent in the process. The low-level and mid-level jets are poised to couple over the central Plains Friday afternoon and evening, supporting scattered to widespread thunderstorms, with organized severe potential possible. ....Central Plains... By Friday afternoon, northwestward return flow of moisture over the central Plains will transport at least low to mid 60s F surface dewpoints up to central NE, where an effective warm front will become established. As stronger mid-level west-southwesterly winds begin to overspread the warm sector, 7-8 C/km mid-level lapse rates should become common, contributing to around 1500 J/kg MLCAPE. Near the warm front, the aforementioned coupling of the low- and mid-level jets supports enlarged hodographs with appreciable curvature and some elongation. Strong deep-layer ascent should support supercell development during the afternoon, with large hail, severe gusts, and perhaps a couple of tornadoes possible (especially with storms that can remain discrete and anchored along the warm front). It is unclear how far southeast storms will initiate into KS, with severe potential highly dependent on the track of the ejecting mid-level trough and accompanying upper support. By evening, storms could grow upscale into an MCS from southern SD into NE as low-level convergence is augmented by the terminus of a low-level jet. Under this scenario, severe gusts would become the main threat. ....Southeast Coastline... A surface low is expected to meander northward along the Carolina coastline through Friday, resulting in scattered thunderstorms moving ashore. At the moment, the northeast quadrant of this cyclone is expected to remain just offshore (per latest guidance consensus). However, any westward shift in the track may support the influx of a higher low-level theta-e airmass, which could coincide with stronger low-level shear. Should this scenario become more apparent, severe probabilities may be introduced in future outlooks. ...Squitieri.. 09/20/2023 $$ = = = 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) .