Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 08 2023 07:22:30 ACUS03 KWNS 080722 SWODY3 SPC AC 080721 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0221 AM CDT Tue Aug 08 2023 Valid 101200Z - 111200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHERN PLAINS...AND FROM THE TENNESSEE VALLEY TO THE COASTAL CAROLINAS AND SOUTHEAST VIRGINIA... ....SUMMARY... Isolated strong to severe thunderstorms are expected across parts of the northern Plains, and from the Tennessee Valley to the coastal Carolinas/southeast Virginia on Thursday. ....Synopsis... A midlevel shortwave trough will pivot east from the OH/TN Valley to offshore the Mid-Atlantic coast on Thursday. Meanwhile, upper ridging over the northern/central Plains will flatten and moderate northwesterly deep-layer flow will overspread the northern Plains to the Upper Midwest. At the surface, low pressure will move from the upper OH Valley to offshore the southern New England coast by Thursday evening. A composite cold front/outflow will move south/east across the central/southern Appalachians toward the coastal Carolinas through the forecast period. Across the northern Plains, a surface low over the Dakotas will develop eastward toward MN. A front attendant to the low will move east across the northern Plains during the afternoon into the overnight. ....TN Valley to the Carolinas/southeast VA... Severe potential will be heavily influenced by the evolution of convection in the Day 2/Wed period. This will determine where any morning convection and/or outflow/effective frontal positions are located on Thursday as the mid/upper trough pivots east. Nevertheless, a seasonally moist airmass amid moderate deep-layer westerly flow will support some severe potential from the TN Valley into the Carolinas/southeast VA. ....Northern Plains... Southerly low-level flow will transport 60s F surface dewpoints northward ahead of the deepening surface low and cold front. This will support a somewhat narrow corridor of moderate instability by afternoon as a midlevel shortwave impulse migrates east toward the region, flattening the upper ridge. Thunderstorms are expected to develop ahead of the front by mid/late afternoon and spread east through the evening. Thunderstorm coverage is uncertain, but at least isolated strong/severe storms are expected, posing a risk for large hail and damaging gusts. Backed low-level flow and a warm front oriented northwest to southeast across the area will enhance low-level SRH and a tornado also could occur. If confidence in greater storm coverage increases, upgraded severe probabilities may become necessary in subsequent outlooks. ...Leitman.. 08/08/2023 $$ = = = 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) .