Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 19 2025 07:13:42 ACUS03 KWNS 190713 SWODY3 SPC AC 190712 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 AM CDT Fri Sep 19 2025 Valid 211200Z - 221200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Thunderstorms are expected from the Great Lakes to the central Plains on Sunday. Severe weather potential remains uncertain. ....Synopsis... The overall mid-level pattern will feature a trough across the central CONUS with a ridge to the west and east. This pattern will become more zonal through the period with multiple embedded mid-level shortwave troughs extending from the East Coast to the Pacific Northwest. While the overall pattern remains consistent between guidance, the low-amplitude and progressive nature of the pattern will lead to considerable uncertainty about the timing and amplitude of the mid-level shortwave troughs. ....Ohio Valley... Within the overall mid-level trough across the Upper Midwest, a secondary positively tilted trough is forecast to move from southern Canada and into the Upper Midwest and eventually take on a more neutral tilt. The strength of this trough will have significant implications on the overall threat across the Ohio Valley on Sunday. A stronger solution, such as the ECMWF, would result in a more pronounced surface low and a trough/cold front across the Ohio Valley. In this scenario, instability and shear would support some severe weather potential Sunday afternoon/evening. Some guidance, such as the GFS, has a less amplified mid-level shortwave trough and minimal surface reflection. This GFS solution is much less favorable for severe weather potential across the Ohio Valley on Sunday. Due to these uncertainties, no probabilities have been added at this time, but may be needed in later outlooks. ....Central Plains... A moist airmass is expected across the Plains on Sunday with moderate instability expected by Sunday afternoon. Overall forcing will be relatively weak, but an uncapped airmass with weak height falls will likely support scattered thunderstorm activity during the afternoon. Mid-level flow will be quite weak (15 to 20 knots) and therefore, organized severe weather potential should remain mostly low. ...Bentley.. 09/19/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .