Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 28 2024 09:01:17 ACUS48 KWNS 280901 SWOD48 SPC AC 280859 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Sun Apr 28 2024 Valid 011200Z - 061200Z ....DISCUSSION... ....D4/Wednesday - Central and southern Plains... Extended-range guidance generally depicts a broad upper-level trough gradually moving eastward across the western CONUS on Wednesday, though differences remain regarding the amplitude of this trough. Downstream of the trough, a surface low is forecast to deepen across the south-central High Plains, with rich low-level moisture streaming northward along/east of a developing dryline and south of a northward-moving warm front. Moderate to strong buoyancy may develop across the warm sector Wednesday afternoon, and scattered thunderstorm development will be possible along/east of the dryline and also near the warm front. While mid/upper-level flow is currently forecast to remain rather modest, deep-layer shear may be sufficient to support some organized convection. With most extended-range guidance depicting scattered thunderstorm development during the afternoon and evening within a relatively favorable environment, a 15% area has been added for parts of the central/southern Plains, where confidence in an organized severe threat is currently highest. Some guidance suggests the threat could extend into parts of southwest and deep south TX, in advance of a low-amplitude subtropical shortwave trough, though uncertainty remains rather high regarding this potential. ....D5/Thursday - Central and southern Plains into the MS Valley... A continuation of severe potential is expected into Thursday across parts of the central/southern Plains and potentially into the mid/upper MS Valley, with moderate to locally strong instability expected again during the afternoon across the warm sector of a northeastward-moving cyclone. However, predictability begins to decrease at this forecast range regarding timing of a cold front that is forecast to move southeastward and potentially provide a focus for thunderstorm development during the afternoon and evening. ....D6/Friday - D8/Sunday... A notable increase in spread amongst extended-range guidance is noted by D6/Friday into the weekend. In general, a cold front will likely continue moving southeastward before stalling across parts of southern Plains into the Southeast. Rich low-level moisture and stronger instability may be maintained across parts of TX, but organized severe potential in that area remains very uncertain at this time. ...Dean.. 04/28/2024 = = = 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) .