Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jun 21 2025 08:43:59 ACUS48 KWNS 210843 SWOD48 SPC AC 210842 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CDT Sat Jun 21 2025 Valid 241200Z - 291200Z ....DISCUSSION... ....D4/Tuesday... Aside from some modest deamplification, little change to the large-scale pattern is expected on Tuesday. An upper trough will remain over the western CONUS, while an upper ridge persists over the East. Scattered to numerous thunderstorms will again be possible along the western and northern periphery of the upper ridge, from the central/southern High Plains into the Upper Midwest. Deep-layer flow will generally be modest, but some severe threat could evolve in the vicinity of an outflow-influenced front, in the presence of favorable low-level moisture and moderate to strong buoyancy. Farther east, a cold front is forecast to move southward across parts of northern New England. Guidance varies regarding the extent to which stronger deep-layer flow and large-scale ascent lag behind the front, but moderate to strong buoyancy could support at least an isolated severe threat during the afternoon and evening. ....D5/Wednesday... Continued modest weakening of both the western trough and eastern ridge is generally forecast on Wednesday. Scattered to numerous thunderstorms will again be possible from the High Plains into the Midwest, Great Lakes, and Northeast, along the periphery of the ridge. Deep-layer flow is expected to be relatively weak across most areas, but mesoscale corridors of somewhat greater severe threat could evolve within this pattern. ....D6/Thursday - D8/Saturday... Predictability of the large-scale pattern begins to notably decrease by the end of next week. In general, an upper ridge may persist over the Southeast, while one or more mid/upper-level shortwave troughs move across the northern CONUS. This pattern may eventually yield an increasing threat for organized severe storms across the northern Rockies/Plains and Upper Midwest, but details are very uncertain at this forecast range. ...Dean.. 06/21/2025 = = = 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) .