Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 10 2023 05:09:17 ACUS01 KWNS 100509 SWODY1 SPC AC 100507 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1207 AM CDT Thu Aug 10 2023 Valid 101200Z - 111200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS...AND OVER PARTS OF THE CAROLINAS INTO FAR SOUTHEAST VIRGINIA... ....SUMMARY... Strong to severe thunderstorms are possible across parts of the northern Plains, and from the Tennessee Valley to the Mid-Atlantic on Thursday. ....Southeast to Mid-Atlantic Coast... A midlevel shortwave trough will be oriented over the OH/TN Valley vicinity this morning, and pivot east/northeast through the day, moving offshore the Mid-Atlantic coast by late evening. A belt of 40-60 kt 500 mb west/southwest flow will overspread the region, supporting organized convection, as effective shear magnitudes approach 30-40 kt. An MCS will likely be ongoing over the southern Appalachians this morning, and may deteriorate as it shifts east through midday. A second area of thunderstorms may then develop ahead of an eastward-progressing surface low over NC. A moist airmass, with dewpoints generally in the upper 60s to mid 70s F will support moderate to strong destabilization by afternoon. Bowing clusters and perhaps a couple of discrete cells are expected across parts of SC/NC toward coastal SE VA. Isolated to scattered damaging gusts and a couple of tornadoes are possible. Further to the west, scattered thunderstorms are expected to develop from northeast MS into AL/GA along residual outflow from prior convection. While vertical shear will be somewhat weaker across this area, moderate to strong instability and a very moist airmass will support clusters of storms capable of isolated damaging gusts. ....Northern Plains vicinity... The upper ridge over the region will shift east toward the upper Great Lakes today as a weak midlevel shortwave impulse migrates east from the northern Rockies to the Upper MS Valley. At the surface, a cold front will develop eastward across the Dakotas and NE during the afternoon/evening. Modest boundary-layer moisture amid steep midlevel lapse rates will foster MLCAPE around 1000-2000 J/kg. Modestly veering wind profiles, and around 30 kt 0-6 km shear, will support a mix of semi-discrete cells and clusters. A deeply mixed boundary-layer will support strong/severe gusts while elongated/straight hodographs above 2-3 km amid steep midlevel lapse rates suggest large hail also will be possible. ....Southern New England... A weak surface low and cold front will shift east across New England during the afternoon/evening. A seasonally moist airmass will be in place. However, poor midlevel lapse rates and muted heating due to cloud cover will largely limit severe potential, though a few strong gusts are possible with storms across Upstate NY eastward. The best chance for a severe storm appears to be closer to coastal southern New England where a better overlap of deeper boundary-layer moisture and stronger surface heating will occur. A few strong gusts and a tornado will be possible within this environment. ...Leitman/Moore.. 08/10/2023 $$ = = = 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) .