Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jul 28 2023 17:32:21 ACUS02 KWNS 281732 SWODY2 SPC AC 281730 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri Jul 28 2023 Valid 291200Z - 301200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF SOUTHERN NEW ENGLAND AND THE MID-ATLANTIC...PARTS OF THE CENTRAL HIGH PLAINS... ....SUMMARY... Widely scattered to scattered strong to severe thunderstorms are possible over southern New England into the Mid Atlantic states on Saturday. Damaging gusts are the primary hazard. Widely scattered severe storms are also possible over the north-central Great Plains late Saturday into Saturday night. ....Synopsis... The upper-level ridge centered over the Divide will amplify on Saturday. Some amplification of the cyclonic flow aloft over the Northeast is also expected. At the surface, a frontal boundary will continue to sag southward within the Plains into the Northeast. This front will likely become more diffuse with time, however. Farther west, modest moist upslope flow will occur in the central/northern High Plains behind the boundary. ....Mid-Atlantic into southern New England... Widely scattered to scattered storms are expected to develop by afternoon either along the front or along a surface trough near the Blue Ridge. Despite modest mid-level lapse rates, strong surface heating and a very moist boundary layer will support moderate to strong buoyancy (2000-3000 J/kg MLCAPE). The greatest values will likely occur within central/eastern Virginia into perhaps the Delmarva. Farther north, more limited heating and weaker mid-level lapse rates will limit overall destabilization. With the amplifying upper-level pattern, moderate mid-level winds will exist as far south as the northern Mid-Atlantic and decrease fairly rapidly to the south. That being said, the overlap of the most buoyant air and the greater deep-layer shear will not be spatially broad. Given the degree of buoyancy, damaging downburst winds are the expected primary threat with isolated large hail possible with initial storm development. A complicating factor in the forecast will be the timing and location of an MCV moving out of the Great Lakes region. Depending on where this feature is located, an area of greater mesoscale shear and storm coverage could develop within a zone from central Virginia into the Delmarva. Confidence remains too low for an increase in wind probabilities. ....Black Hills Vicinity... An uncertain forecast is evident for the region. Storms associated with a MCV moving out of Montana could be ongoing early in the period. While these storms would likely be elevated, strong deep-layer shear and adequate elevated buoyancy would promote some risk for large hail and perhaps a strong/severe wind gusts. Outflow from this early activity could also provide the focus for additional convective development farther south into northwest Nebraska. Model spread remains high in terms of the expected evolution. The Slight risk will be maintained this outlook cycle, though confidence in any one eventual scenario is low. ....Mid-Mississippi and Lower Ohio Valleys... Moderate to strong buoyancy is anticipated south of the surface front. Models suggest the MCV moving into the central Plains will likely provide lift for eventual development of a cluster of thunderstorms. Deep-layer shear will not be overly strong, particularly farther south from the boundary, but should be sufficient for modest storm organization. The timing and location of development is uncertain, but intensification could occur within northern/eastern Missouri. Damaging wind gusts would be the primary threat, though isolated large hail could also occur. ....Northern Plains... Storm coverage will likely be limited given the amplification of the ridge aloft. However, enough low-level moisture flowing into the terrain should allow a few storms to develop in the northern Rockies. Guidance also suggests development is possible in southern Alberta with eventual movement into northeast Montana and far western North Dakota. Shear profiles would support supercells capable of large hail and strong/severe wind gusts. ...Wendt.. 07/28/2023 $$ = = = 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) .