Subj : MESO: Mesoscale Discussion 1879 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Aug 07 2023 16:14:51 ACUS11 KWNS 071614 SWOMCD SPC MCD 071614=20 MDZ000-PAZ000-DCZ000-VAZ000-WVZ000-NCZ000-071815- Mesoscale Discussion 1879 NWS Storm Prediction Center Norman OK 1114 AM CDT Mon Aug 07 2023 Areas affected...portions of Virginia into the West Virginia Panhandle...central Maryland...central and southern Pennsylvania Concerning...Severe potential...Tornado Watch likely=20 Valid 071614Z - 071815Z Probability of Watch Issuance...95 percent SUMMARY...The severe threat is increasing across portions of the central Appalachians into the Mid Atlantic region. Widespread damaging gusts and at least a few tornadoes are expected. A Tornado Watch will be needed to address the increasing severe threat. DISCUSSION...Ample insolation across the central Appalachians into the Mid Atlantic has allowed surface temperatures to already reach the upper 70s to mid 80s F amid 70+ F dewpoints. Furthermore, a plume of 6.5+ C/km mid-level lapse rates is beginning to overspread the warming, moist boundary layer as a 50+ kt westerly mid-level jet streak impinges on the central Appalachians. SBCAPE has already reached 2500 J/kg in some locales and may increase to over 3000 J/kg by early afternoon. Furthermore, a near 100 kt upper-level jet streak is rapidly approaching the central Appalachians, which in turn should support a strong low-level mass response, favoring a northeastward translation of a 30+ kt southwesterly 850 mb jet this afternoon. Within a few hours, the aforementioned buoyancy and the coupled strong low-level and mid/upper jet streaks should be positioned over the central Appalachians/Mid Atlantic to support an appreciable severe threat, both with storms approaching from the west, and with newer storms that can develop and mature/become sustained. Strong directional and speed shear through the troposphere will support supercells as the initial threat (as well as with any storms that can remain discrete). However, strong forcing with the approaching mid-level trough will also encourage QLCS development. With both storm modes, numerous to potentially widespread damaging gusts are expected and a few 65+ kt gusts are possible. Large hail would be most likely with supercell structures. Tornado potential will exist with any supercell structures and stronger QLCS circulations, and a strong tornado cannot be ruled out, especially if a longer-lived semi-discrete supercell can materialize.=20 A Tornado Watch will be needed pending favorable convective trends. ...Squitieri/Guyer.. 08/07/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8pwb1N5hvXVKu39L0jvLYNqSHESVEzHMlYsTlzMESu2CkasrSTCKlCXLXJbvvzPiIn7x6P4AL= GtWFNy15iz8M2eVup8$ for graphic product... ATTN...WFO...AKQ...CTP...LWX...RNK...RLX...MRX... LAT...LON 36628168 38837939 40017881 40907833 41087772 40897722 39947663 39507645 38967650 38517676 38167733 37547833 36847935 36468018 36458107 36628168=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) .