Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 03 2024 05:36:05 ACUS01 KWNS 030536 SWODY1 SPC AC 030534 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1234 AM CDT Sat Aug 03 2024 Valid 031200Z - 041200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL/EASTERN NORTH CAROLINA INTO SOUTHEAST PENNSYLVANIA AND SOUTHERN NEW JERSEY...AND ACROSS EASTERN SOUTH DAKOTA...CENTRAL/SOUTHERN MINNESOTA AND EXTREME NORTHWEST IOWA... ....SUMMARY... Scattered severe storms are most likely this afternoon and evening from eastern South Dakota into Minnesota with damaging winds and hail possible. Scattered thunderstorms producing damaging gusts are also expected across parts of the North Carolina Piedmont into the Mid-Atlantic vicinity. A developing tropical cyclone may also impact the Florida Keys and western Florida Peninsula. Meanwhile, isolated strong storms are possible across the southern High Plains. ....Mid-Atlantic Vicinity into SC/GA... An upper trough oriented from the lower Great Lakes/Ohio Valley to northern AL/GA will shift east toward the northern Appalachians and Mid-Atlantic vicinity through tonight. This will result in a belt of 25-35 kt southwesterly midlevel flow overspreading the NC/VA Piedmont, northward toward southern New England. A surface front will stall from eastern PA southwestward along the Blue Ridge Mountains and into north GA. To the east of this surface boundary, a very moist airmass will be in place, with dewpoints in the 70s F. This will aid in moderate destabilization, with MLCAPE values 1500-2000 J/kg common. A few pockets with higher instability are possible, but poor midlevel lapse rates will limit stronger destabilization on a large scale. Nevertheless, 25-35 kt effective shear magnitudes will support strong to severe thunderstorms. Thunderstorm clusters will be possible, and scattered wind damage is expected with this activity. A corridor of greater severe potential is expected from central NC into southeast PA/southern NJ, where greater storm coverage is expected along with increased potential for forward-propagating clusters. A Slight (level 2 of 5) risk has been included for this corridor. ....Eastern Dakotas/Upper Midwest... Moderate northwesterly mid/upper flow will overspread the region on the western periphery of a large Hudson Bay upper cyclone. A weak surface low is forecast to develop over central SD, with a warm front extending from southwest MN into central/eastern IA, and a cold front developing southward across northern MN and the Dakotas. A wedge of mid 60s to low 70s F dewpoints between these surface features will foster moderate to strong destabilization during the afternoon amid steep midlevel lapse rates. Vertically veering wind profiles and elongated/straight hodographs, along with effective shear magnitudes around 25-35 kt, should favor supercells. Damaging gusts and large to very large hail will be possible with this activity. Initial cellular activity may develop into a small MCS, transitioning the risk to mainly damaging winds during the evening. ....Southwest FL Peninsula... Per latest NHC guidance, Tropical Depression Four is forecast to become a tropical storm by this evening as the system tracks over the eastern Gulf of Mexico. Scattered thunderstorms will overspread the southern Peninsula, where low/mid level east/southeasterly flow will increase through the period. Sufficient low-level instability and 0-1 km SRH increasing to greater than 200 m2/s2 will support some risk for a couple of tornadoes. ....Southern High Plains... A convectively enhanced vorticity max is forecast to develop south across the central/southern High Plains vicinity this afternoon/evening. Vertically veering wind profiles will support rather robust effective shear magnitudes greater than 40 kt. Boundary-layer moisture will remain modest, but steep midlevel lapse rates will aid in at least weak destabilization (MLCAPE around 500-1000 J/kg) sufficient for high-based thunderstorm development. A deeply mixed boundary layer with inverted-v sub-cloud thermodynamic profiles will support strong outflow winds with any storms that develop. If any longer-lived cells can be maintained, isolated large hail is also possible. ...Leitman/Thornton.. 08/03/2024 $$ = = = 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) .