Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Oct 27 2024 09:00:24 ACUS48 KWNS 270900 SWOD48 SPC AC 270858 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Sun Oct 27 2024 Valid 301200Z - 041200Z ....DISCUSSION... ....Wednesday/Day 4 and Thursday/Day 5... An upper-level trough is forecast to move eastward into the central Rockies and northern Plains on Wednesday, as an associated mid-level jet translates eastward into the mid Missouri Valley. At the surface, a cold front is forecast to move east-southeastward across the Upper Midwest and central Plains. Scattered thunderstorm development is expected along and ahead of the front during the afternoon. Sufficient instability combined with strong low-level flow, and lift associated with the upper-level trough will be favorable for severe storms across parts of the region. The most favorable area for severe storms appears to be from north Texas and Oklahoma northeastward into western and northern Missouri. GFS forecast soundings along this corridor during the late afternoon suggest that MLCAPE will peak in the 1000 to 1500 J/kg range. 0-6 km shear is forecast to be between 40 and 50 knots, with 700-500 mb lapse in the 7 to 7.5 C/km range. If this environement can materialize, supercell development with large hail and severe wind gusts could occur. A chance for very large hail will be possible with the more intense cells. An isolated tornado threat also appears possible. On Thursday, the upper-level trough is forecast to move into the Great Lakes region, as the cold front advances southeastward into the Ohio Valley and Ark-La-Tex. Isolated strong to severe storms will be possible along parts of the front where surface temperatures are able to warm sufficiently. The strongest low to mid-level flow is forecast over the mid Mississippi and lower Ohio Valley suggesting that the potential for organized severe convection could be displaced away from the strongest instability. Even so, instability is forecast to remain weak which appears to be the main limiting factor. ....Friday/Day 6 to Sunday/Day 8... On Friday, an upper-level trough is forecast to move northeastward into the north-central U.S., as moisture return takes place in western parts of the southern Plains. It appears that thunderstorm development will be possible across parts of west Texas within the northwestern part of a moist airmass. Large-scale ascent is forecast to remain relative weak suggesting that any severe threat could be isolated. On Sunday, southwesterly mid-level flow is forecast over the Great Plains, as low-level moisture advection continues. Scattered thunderstorms will be possible within this moist airmass as surface temperatures warm during the day. At this time, forecast instability and shear appear marginal for severe storms, and any organized convection should be relatively isolated. ...Broyles.. 10/27/2024 = = = 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) .