Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Aug 09 2023 17:31:11 ACUS02 KWNS 091731 SWODY2 SPC AC 091729 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Wed Aug 09 2023 Valid 101200Z - 111200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS AND SOUTHEASTERN VIRGINIA...AND OVER PORTIONS OF THE NORTHERN PLAINS/MID MISSOURI VALLEY AREA... ....SUMMARY... Strong to severe thunderstorms are possible across parts of the northern Plains, and from the Alabama vicinity to the coastal Carolinas/southeast Virginia on Thursday. ....Synopsis... Within the belt of moderate west-southwesterly mid-level flow across the U.S. Thursday, two short-wave troughs will be associated with two distinct areas of convective/severe potential. The first of these troughs is expected to cross the central and southern Appalachians region during the day, and then should move off the Mid-Atlantic/Carolina Coasts during the evening. Meanwhile, the second trough -- expected over the northern and central High Plains area early in the day --will move east-southeastward across the Plains through the afternoon, and to the Mid and Upper Mississippi Valley region by the end of the period. At the surface, a compact low/frontal system is forecast to cross the central and southern Appalachians region early, and then across Virginia and the Carolinas through the day. The front should clear the East coast from New Jersey southward through late afternoon/early evening, with the low then continuing across southern New England into the overnight hours. Meanwhile, a weaker low/trough is forecast to cross the Plains through the afternoon/evening hours. ....Parts of the Southeast and Mid-Atlantic regions... Thunderstorms -- possibly in the form of an at least loosely organized band -- will likely be ongoing at the start of the period across the western Carolinas vicinity. These storms may be accompanied by ongoing risk for locally damaging wind gusts, and possibly a tornado. Some decrease in intensity may occur with this convection into the afternoon, though indications are that subsequent storm redevelopment may occur across the southeastern Virginia/eastern Carolinas area during the afternoon, ahead of the advancing cold front. These storms would also likely pose a risk for damaging winds locally, along with potential for hail and a tornado or two before storms move offshore during the evening. ....Northern Plains and Mid-Missouri Valley area... Diurnal heating ahead of an advancing/weak cool front will result in moderate afternoon warm-sector destabilization across the central and northern Plains region. As the boundary advances in tandem with weak upper short-wave troughing, isolated to widely scattered storm development is expected by latter stages of the afternoon period. CAM output from various models differs, with respect to storm coverage, though several suggest upscale/linear growth with time, and possibly even an eventual southeastward-moving, bowing MCS across the Mid-Missouri Valley area during the evening and possibly into the overnight hours. In any case, with 35 to 45 kt mid-level west-northwesterlies across the area, atop low-level southerly warm-sector winds, shear will support potential for organized storms, and attendant risks for locally damaging wind gusts, and severe-caliber hail. A tornado cannot be ruled out, mainly across the eastern South Dakota vicinity where slightly backed low-level flow is anticipated ahead of the weak surface low. While storm coverage remains uncertain, current indications are that upgrade to SLGT risk is warranted for the afternoon and evening hours. ....Southern New England... As a deepening surface low crosses southern New England during the second half of Thursday, meager CAPE may support a few thunderstorms. Within the northeast quadrant of the low -- across southeastern New England -- a very favorable flow field is anticipated, with low-level winds veering/increasing rapidly with height. While the thermodynamic deficiency that is anticipated should substantially limit overall potential, conditional risk for a couple of stronger wind gusts and/or a tornado or two is evident, mainly from late afternoon through late evening, until the low and associated front sweep northeastward/offshore. ...Goss.. 08/09/2023 $$ = = = 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) .