Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Apr 17 2023 09:02:15 ACUS48 KWNS 170902 SWOD48 SPC AC 170900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Mon Apr 17 2023 Valid 201200Z - 251200Z ....DISCUSSION... ....Thursday/Day 4... An upper-level low is forecast to move into the Northern Plains on Thursday, as an associated trough moves eastward into the southern and central Plains. As the trough approaches, a southern Plains dryline is forecast to move quickly eastward into the western Ozarks, with a cold front overtaking the dryline. Surface heating and low-level convergence along these features will likely result in convective initiation during the afternoon. Thunderstorms are expected to develop from the mid Mississippi Valley southwestward across the Ozarks into northeast Texas. Moderate deep-layer shear and steep lapse rates near the instability axis will likely be favorable for severe storms during the late afternoon and evening. Supercells will be capable of large hail and wind damage. The more organized multicell line segments could also have a wind-damage threat. ....Friday/Day 5 and Saturday/Day 6... The upper-level trough, and associated cold front is forecast to move eastward across the lower to mid Mississippi Valley on Friday. As surface temperatures warm during the day, thunderstorm development will be likely near and ahead of the front. Although there is some differences among the solutions concerning frontal-timing, the models are in agreement that enough instability and deep-layer shear will be present for a severe threat. The current thinking is that the severe threat will be greatest across the lower Mississippi, as the mid-level jet digs southeastward into the region Friday afternoon. Large hail and wind damage will be possible with rotating storms and organized line segments. Further north-northeast into the Ohio Valley, an isolated severe threat will also be possible Friday afternoon. Wind damage and hail are expected to be the primary threats. The upper-level trough, and associated front is forecast to move eastward across the Southeast on Saturday. Thunderstorms again will be possible along and ahead of the front as surface temperatures warm during the day. Although an isolated severe threat will be possible during the mid to late afternoon, the potential may be lessened by weaker moisture return ahead of the front. ....Sunday/Day 7 and Monday/Day 8... A large area of high pressure is forecast to move into the central and eastern United States on Sunday and Monday. This will likely minimize the potential for thunderstorm activity over most of the nation. ...Broyles.. 04/17/2023 = = = 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) .