Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed May 21 2025 08:52:58 ACUS48 KWNS 210852 SWOD48 SPC AC 210850 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Wed May 21 2025 Valid 241200Z - 291200Z ....DISCUSSION... Severe weather is possible across portions of the central Plains on Saturday and Sunday as a mid-level trough emerges from the Rockies into the Plains. Upper 60s to low 70s dewpoints will result in strong to very strong instability south of a frontal zone. This front will initially be stationary across Kansas on Saturday before starting to advance south Saturday night and Sunday. Given the instability ahead of this front, widespread storm development is likely. However, the severity of this convection remains questionable. The operational GFS is the most aggressive with severe weather potential as it maintains troughing into the Plains with southwesterly flow around 40 knots forecast across the frontal zone which should provide ample shear for severe storms given the likely instability that will be in place. However, this appears to be an outlier with weaker, more zonal flow preferred by the ECMWF and the ECS and GEFS. Due to this uncertainty regarding the mid-level troughing and shear across the warm sector, severe weather probabilities are not warranted at this time. High pressure will build into much of the eastern CONUS on Day 6/Monday and persist for much of the week. This will shunt a frontal zone and the better moisture closer to the Gulf coast, removed from the stronger mid-level westerlies. Therefore, thunderstorms will be likely along this frontal zone through the week, but organized severe storms are not expected to be that widespread. ...Bentley.. 05/21/2025 = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .