MD 2110 CONCERNING SEVERE POTENTIAL…SEVERE THUNDERSTORM WATCH LIKELY FOR PORTIONS OF THE MID-ATLANTIC INTO THE NORTHEAST
Mesoscale Discussion 2110
NWS Storm Prediction Center Norman OK
0146 PM CDT Fri Sep 08 2023
Areas affected…Portions of the Mid-Atlantic into the Northeast
Concerning…Severe potential…Severe Thunderstorm Watch likely
Valid 081846Z – 082045Z
Probability of Watch Issuance…80 percent
SUMMARY…The threat for scattered damaging winds and isolated large
hail will likely increase this afternoon and warrant Severe
Thunderstorm Watch issuance.
DISCUSSION…In addition to widely spaced convection which has
developed across the coastal Mid-Atlantic and southern New England
along a marine warm front/sea breeze, a gradual increase in
thunderstorm coverage and intensity is expected to occur this
afternoon from parts of VA northeastward into New England as modest
ascent preceding a weak upper trough aids parcels in reaching their
LFC. Initial development over the higher terrain of the Appalachians
and Blue Ridge should move northeastward with time given a fairly
unidirectional southwesterly flow at mid/upper levels. A fairy tight
gradient of instability if present from the southern Mid-Atlantic to
the Northeast, with 1500-2500+ J/kg of MLCPAE present where strong
daytime heating of a rather moist low-level airmass has occurred.
Various VWPs from area radars show weak low-level flow gradually
strengthening to around 25-35 kt, with around 20-30 kt of deep-layer
shear. Multicells should be the dominant convective mode, with
marginal supercells possibly posing an isolated threat for large
hail initially. With time, damaging winds around 50-60 mph will
likely become the main concern as multiple clusters form and
subsequently spread northeastward through the evening. The greatest
threat for damaging winds will probably be focused in a fairly
narrow corridor where low-level lapse rates have become steepened
along/near the instability gradient/weak front that extends from
southwest to northeast across the Mid-Atlantic into New England.
Given the ongoing coastal convection, which has already produced
some hail/damaging wind reports, and expectations for increasing
thunderstorm coverage this afternoon, one or more Severe
Thunderstorm Watches will likely be needed.
..Gleason/Guyer.. 09/08/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…GYX…BOX…BTV…OKX…ALY…PHI…BGM…CTP…
LWX…
LAT…LON 38217935 39907873 42337506 43517257 44087095 43467032
42347128 40917331 40177413 38927548 38157822 38217935
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