Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Nov 29 2022 10:02:34 ACUS48 KWNS 291002 SWOD48 SPC AC 291001 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0401 AM CST Tue Nov 29 2022 Valid 021200Z - 071200Z ....DISCUSSION... ....Friday/Day 4 and Saturday/Day 5... West-southwest mid-level flow will be in place across much of the United States on Friday. In response to the southern edge of a low-level jet, a moist airmass is forecast to spread northward into east Texas and Louisiana. Elevated thunderstorms will be possible along and near the axis of strongest low-level flow, mainly during the overnight period from the lower Mississippi Valley into the Ohio Valley. An isolated severe threat could accompany some of the stronger storms, but any potential should be marginal due to a lack of instability. On Saturday, an area of high pressure is forecast to move southeastward into the central U.S. A moist airmass is expected to remain across parts of the Gulf Coast region, where isolated thunderstorm development will be possible. Weak instability should again be a limiting factor, but a marginal severe threat would be possible in areas that can destabilize the most. At this time, the thinking is that any threat will remain marginal again on Saturday. ....Sunday/Day 6 to Tuesday/Day 8... On Sunday, a low-amplitude anticyclonic wave is forecast to move eastward across the central U.S., as an upper-level trough impacts the southern part of the West Coast. Although a moist airmass should be in place across the Gulf Coast region, thunderstorm development should remain relatively isolated during the day. Convective coverage is expected to increase throughout the evening and overnight period as a low-level jet strengthens. An isolated severe threat will be possible near this feature from the southern Plains and Ozarks, eastward across the mid Mississippi Valley, due to warm advection and adequate effective shear. The upper-level trough is forecast to move quickly eastward across the Desert Southwest on Monday, and into the central U.S. by Tuesday. Concerning this system, the models are in reasonably good agreement, with a moist sector moving northward across the lower to mid Mississippi Valley. The severe threat would likely be the greatest on Monday evening, when the combination of moisture, instability, shear and lift is forecast to be the greatest. This area could encompass the Ozarks and mid Mississippi Valley. The main problem in forecasting a threat area on Monday/Day 7, is that the models have not shown enough run-to-run consistency. If the forecast trough is much slower than forecast, then any potential threat area would be shifted one or more states to the west. A somewhat cautious approach seems valid due to the potential for large model error, especially at this extended range in the forecast period. ...Broyles.. 11/29/2022 = = = 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) .