SPC MD 1725

MD 1725 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHEAST NEW ENGLAND

Mesoscale Discussion 1725
NWS Storm Prediction Center Norman OK
0409 AM CDT Wed Sep 30 2020

Areas affected...Southeast New England

Concerning...Severe potential...Watch unlikely 

Valid 300909Z - 301045Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated damaging gusts will be possible this morning,
prior to frontal passage.

DISCUSSION...A narrow band of shallow frontal convection (without
lightning) is moving eastward into western MA/CT and Long Island. 
The convection is focused along a surface cold front that will move
eastward across southern New England this morning, as a surface low
near the NY/MA border moves north-northeastward and deepens in
advance of an ejecting shortwave trough over VA/MD/PA.  The primary
limiting factor for a severe-storm threat will be poor lapse rates
aloft and near the surface, leading to very weak buoyancy despite
boundary-layer dewpoints of 68-70 F.  Still, the near moist neutral
profiles, strong forcing for ascent along the front, and 60-70 kt
flow to within a km of the ground will support some potential for
downward momentum transfer in the stronger convective elements.  The
threat for isolated damaging winds will persist until frontal
passage occurs across eastern MA/Cape Cod around 14z.

..Thompson.. 09/30/2020

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GYX...BOX...OKX...ALY...

LAT...LON   40677307 41567317 42457295 43167248 43277170 43027075
            42197050 41577073 41147115 40677307 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1725.html