Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Aug 02 2023 08:16:01 ACUS48 KWNS 020815 SWOD48 SPC AC 020814 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0314 AM CDT Wed Aug 02 2023 Valid 051200Z - 101200Z ....DISCUSSION... ....Day 4/Sat - Central Plains vicinity... Forecast guidance has trended toward a less amplified midlevel trough migrating across the northern Plains on Saturday. Nevertheless, a belt of enhanced westerly flow will still reside over the central Plains while a weak surface low shifts east in the vicinity of the NE/SD border. A very moist boundary layer, supporting moderate to strong instability beneath moderate midlevel flow, will support organized thunderstorm develop by late afternoon. A cold front is expected to shift east/southeast across the central Plains toward the Lower MO Valley during the evening/overnight. Development of a severe MCS appears possible, bringing a damaging-wind risk to portions of NE/KS. ....Day 5/Sun - Mid-South to Mid-MS/Lower OH Valleys... The central Plains midlevel trough and surface low will continue east on Day 5/Sun, moving across portions of the Midwest. Forecast guidance varies with intensity of the shortwave trough and the location of the surface low. Nevertheless, a moist and unstable airmass, with at least some enhancement to mid/upper flow, will exist from the Mid-South toward the Lower OH Valley. While confidence is too low to delineate a 15 percent severe area at this time, some severe potential is likely ahead of the eastward-advancing cold front and any ongoing MCS Sunday morning. Severe probabilities likely will be needed once confidence increases in a more focused corridor of greater severe potential across this broad region. ....Days 6-8/Mon-Wed... Some degree of mid/upper troughing will continue eastward across the Midwest toward the eastern U.S. early next week. Large model spread lends to much uncertainty in this time frame. However, some severe potential could spread across parts of the Mid-Atlantic and Northeast on Day 6/Mon depending on the track/timing of the surface low and cold front mentioned in the Days 4-5/Sat-Sun time frame. Many days of convection prior to early next week, and uncertainty regarding evolution of any MCSs from the Day 4-5 period, make predictability too low to include probabilities at this time. ...Leitman.. 08/02/2023 = = = 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) .