Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Oct 08 2023 09:02:11 ACUS48 KWNS 080902 SWOD48 SPC AC 080900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sun Oct 08 2023 Valid 111200Z - 161200Z ....DISCUSSION... An upper trough and associated strong mid-level jet should consolidate and become better defined as they advance eastward across the western CONUS and to the central High Plains on Day 4/Wednesday. Ahead of these features, a surface low should deepen as it develops eastward across KS through Wednesday night. Low-level moisture should continue advecting northward across the southern/central Plains in this time frame. Guidance continues to suggest that a substantial cap will tend to limit convective development through at least Wednesday afternoon. But, robust thunderstorms do eventually appear possible Wednesday evening/night across parts of KS/NE near the surface low as low-level warm advection strengthens. Hail may occur with the strongest cores than can develop, as deep-layer shear should support updraft organization. Primary concerns and potentially limiting factors at this point are the modest low-level moisture forecast and related weak instability. Confidence still remains too low to include a 15% severe area across parts of the central Plains on Wednesday, but at least low severe probabilities appear possible in later outlooks. Medium-range guidance is beginning to come into better agreement with the ejection of the upper trough across the central Plains on Day 5/Thursday. Some severe potential remains evident Thursday afternoon/evening in a narrow corridor ahead of the surface low and cold front/dryline, mainly across eastern KS into western MO and vicinity. Similar concerns remain regarding the quality/depth of low-level moisture and its impact on instability, along with small differences in the placement/amplitude of the upper trough. Still, deep-layer shear associated with a rather strong mid-level jet will likely support thunderstorm organization with any convection that can develop across the warm sector. If current model trends continue and agreement improves slightly, a 15% severe area may be needed for Thursday. The upper trough should continue eastward across the mid MS Valley and Midwest on Day 6/Friday. Uncertainty regarding sufficient instability to support surface-based thunderstorms becomes even greater at this time frame. But, enhanced low/mid-level flow with the maturing cyclone could support some strong/damaging wind potential with any thunderstorms that can form across the OH Valley. Regardless, predictability with the upper trough quickly becomes too low from Friday into early next weekend to confidently delineate organized severe potential across the eastern CONUS. ...Gleason.. 10/08/2023 = = = 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) .