Subj : MESO: Mesoscale Discussion 1282 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 26 2023 16:36:53 ACUS11 KWNS 261636 SWOMCD SPC MCD 261636=20 NYZ000-NJZ000-PAZ000-MDZ000-DEZ000-VAZ000-NCZ000-DCZ000-WVZ000-SCZ000-26190= 0- Mesoscale Discussion 1282 NWS Storm Prediction Center Norman OK 1136 AM CDT Mon Jun 26 2023 Areas affected...Portions of SC...NC...VA...the eastern WV Panhandle...MD...DC...DE...central/eastern PA...NJ...and southern/western NY Concerning...Severe potential...Severe Thunderstorm Watch likely=20 Valid 261636Z - 261900Z Probability of Watch Issuance...95 percent SUMMARY...Scattered to numerous damaging winds and large hail will become an increasing concern this afternoon. Multiple Severe Thunderstorm Watches will likely be needed to address this severe threat over the next couple of hours. DISCUSSION...16Z surface analysis shows a surface low centered over Lower MI with a cold front extending southward from this low across the OH Valley. A weak pre-frontal trough is present along/near the Blue Ridge Mountains into western/central NC. Much of the Mid-Atlantic still has considerable cloudiness early this afternoon, which will hamper diurnal heating to some extent. The clouds across central/eastern VA into MD is associated with a remnant MCV/mid-level vorticity maximum, with weak subsidence noted behind it. Better heating will continue across southwest VA into western NC and much of SC, where less cloud cover exists. Still, a moist low-level airmass is present across the Mid-Atlantic/Carolinas, with generally mid 60s to low 70s surface dewpoints in place. Continued heating of this airmass will likely promote around 1000-2500 J/kg of MLCAPE by mid afternoon, with greater instability expected in the Carolinas where mid-level lapse rates are steepened. Current expectations are for thunderstorms to continue developing across the higher terrain of the Appalachians, and perhaps the surface lee trough, as weak ascent associated with an upper trough/low centered over the Great Lakes overspreads the Mid-Atlantic. Convection is already ongoing across parts of PA and western/southern NY, with a measured severe gust recently recorded at KDKK in far western NY. Weaker forcing across the Carolinas casts some uncertainty regarding overall thunderstorm coverage with southward extent. Better mid-level flow around the base of the upper trough/low should tend to remain over the Carolinas through the day. 30-40 kt of deep-layer shear across NC/SC will support some threat for supercells and large hail with initial development. Across the Mid-Atlantic, effective bulk shear should be somewhat weaker, generally in the 20-30 kt range. Mainly multicells/clusters should be the dominant mode across this region, with perhaps isolated/marginal supercells possible. Wherever enough clearing can occur to promote steep low-level lapse rates, a threat for damaging downdraft winds will exist. Multiple corridors of potentially greater coverage of scattered to numerous damaging gusts are evident based on observational and short-term guidance trends. One such possible corridor is across eastern PA into NJ. Multiple Severe Thunderstorm Watches will likely be needed this afternoon across the Mid-Atlantic and Carolinas to address the increasing threat for damaging winds and severe hail. ...Gleason/Grams.. 06/26/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7nBtWcBEU9QohHM3JtimkBy03hpd4XInCwmlZnxQrxeu-giGd9SGbklISGJn1C7cQ8kIrMveK= Erm6xgEDb0a05lfkfc$ for graphic product... ATTN...WFO...OKX...ALY...PHI...BGM...AKQ...BUF...CTP...LWX... RAH...ILM...RNK...CAE...GSP... LAT...LON 33798208 34798225 36388125 38547930 40737817 42097914 42857863 43337753 43447664 42867540 42117436 41567404 40877377 39577418 38957477 38297507 37287569 36357710 34787913 33498090 33338151 33798208=20 =3D =3D =3D 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) .