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
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