Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 16 2024 08:46:19 ACUS48 KWNS 160845 SWOD48 SPC AC 160844 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0344 AM CDT Fri Aug 16 2024 Valid 191200Z - 241200Z ....DISCUSSION... ....Monday/Day 4 to Wednesday/Day 6... An upper-level ridge is forecast to remain over the High Plains from early to mid week, as an upper-level trough moves slowly eastward across the eastern U.S. Surface high pressure, associated with the trough is forecast to move from the middle to upper Mississippi Valley on Monday to the middle and upper Atlantic Seaboard by Wednesday. Due to this high, the airmass across much of the eastern third of the U.S. will likely become drier and less unstable from Monday to Wednesday, making conditions less favorable for severe storms. Further to the west, a south-to-north corridor of moderate instability is forecast to develop each day, remaining in a similar position across the central and northern Plains. Thunderstorms will be possible each afternoon and evening to the east of the ridge near the axis of instability. It appears that deep-layer shear will be relatively weak near instability axis, which will favor less storm organization. Still, a marginal severe threat will be possible due to the strong instability. ....Thursday/Day 7 and Friday/Day 8... The upper-level ridge in the north-central U.S. is forecast to move eastward from the northern Plains on Thursday into the western Great Lakes region by Friday. An axis of moderate to strong instability is forecast to remain over the central and northern Plains. Thunderstorms that form each afternoon close the instability axis will have a chance be severe. Although there is a lot of uncertainty this far out in the forecast cycle, the subsidence and weaker deep-layer shear associated with the upper-level ridge, should negatively impact severe potential. However, instability could be strong enough for a marginal severe threat, mainly during the afternoon and evening on Thursday and Friday. ...Broyles.. 08/16/2024 = = = 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) .