Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 02 2023 12:53:06 ACUS01 KWNS 021253 SWODY1 SPC AC 021251 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Sun Jul 02 2023 Valid 021300Z - 031200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS TN/KY... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN AR TO THE MID-ATLANTIC...AND ACROSS THE SOUTHERN HIGH PLAINS... ....SUMMARY... Scattered severe thunderstorms with damaging winds and isolated large hail will be possible this afternoon/evening from Tennessee and Kentucky to the Mid-Atlantic, and across northeast New Mexico and the northwest Texas Panhandle. ....KY/TN and vicinity through early tonight... Within a largely zonal flow regime, a midlevel shortwave trough will progress eastward from the mid MS Valley to the OH Valley by tonight. Accompanying this trough, a belt of 40-50 kt midlevel flow will overspread areas along and south of the OH River, across KY/TN through this evening. Likewise, a weak surface cyclone in northern IL will move eastward to OH by tonight, while a trailing cold front moves slowly southeastward. The cold front and zone of ascent preceding the midlevel trough will support scattered to numerous thunderstorms through tonight, with the attendant threats of damaging winds and large hail. In the wake of weakening morning convection across KY, boundary-layer dewpoints in the low-mid 70s will spread northeastward from the Mid-South as surface heating in cloud breaks boosts MLCAPE into the 2500-3500 J/kg range with minimal convective inhibition. Thunderstorm development is expected by early-mid afternoon along and ahead of the front across KY/TN and vicinity, and storms will subsequently spread east-northeastward through late evening/early tonight. The increasing mid-upper flow over the warm sector will result in sufficiently long and relatively straight hodographs for supercells and organized clusters capable of producing damaging winds and large hail. An isolated tornado or two may also occur, primarily where storms interact with lingering convective outflow/locally backed near-surface winds. ....Mid-Atlantic this afternoon/evening... A weak surface trough immediately east of the Blue Ridge will help focus scattered thunderstorm development this afternoon from southeast PA across western MD and VA. Midlevel flow will be stronger than previous days and sufficient for organized storm clusters, and perhaps some marginal supercell storms. Though midlevel lapse rates will not be particularly steep, heating of the moist boundary layer (dewpoints in the low 70s) will drive MLCAPE of 1500-2000 J/kg with steepening low-level lapse rates. As a result, the stronger storms this afternoon/evening will be capable of producing damaging winds. ....Southern High Plains this afternoon/evening... A weak perturbation will move southeastward across CO toward the southern High Plains by this evening. Thunderstorm development is expected immediately east of the high terrain in northeast NM by mid afternoon, and storms will then spread southeastward toward the TX Panhandle through early tonight. A deep mixed boundary layer will support MLCAPE up to 1500 J/kg, and DCAPE of similar magnitude. Vertical shear will be rather weak, but thermodynamic profiles will favor clusters of storms capable of producing a few severe gusts this afternoon into this evening. ....MT/ND areas through tonight... A pronounced midlevel low will move over SK while midlevel flow gradually strengthens farther south over MT/northwest ND. In the wake of morning convection, lingering boundary-layer dewpoints in the 60s and convergence along a surface trough could be sufficient for isolated strong thunderstorm development this evening across extreme northeast ND/northwest MN. Isolated strong-severe gusts and large hail will be the main threats for a few hours this evening across northeast ND/northwest MN. Farther west, a cold front will move southeastward into northeast MT/northwest ND this evening through tonight. Thunderstorm coverage looks to remain isolated at best until well after the diurnal heating cycle, and buoyancy overnight will remain rather weak. There will be some increase in vertical shear by tonight along the front, but the weak buoyancy and poor phasing with the diurnal cycle both suggest that the threat for severe storms is too low for an outlook area. ...Thompson/Gleason.. 07/02/2023 $$ = = = 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) .