SPC MD 1620

MD 1620 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF VIRGINIA...WEST VIRGINIA...NORTH CAROLINA...THE DELMARVA

Mesoscale Discussion 1620
NWS Storm Prediction Center Norman OK
0650 PM CDT Fri Aug 28 2020

Areas affected...parts of Virginia...West Virginia...North
Carolina...the Delmarva

Concerning...Severe potential...Watch unlikely 

Valid 282350Z - 290215Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered storms, with isolated severe, may persist well
into the evening from the Appalachians eastward to the Mid Atlantic
Coast.

DISCUSSION...The primary corridor of training storms currently
extends from northern VA into DE, with an outflow boundary drifting
south. Recently, widely spaced cells have developed over western VA
and NC, where the air mass is uncapped and unstable. 

MLCAPE over 2000 J/kg exists across the entire region, with modest
southwesterlies aloft. Given the veering winds with height, storm
mode has been primarily cellular. Weak rotation may occur in some of
these cells this evening as the low-level jet increases.

The combination of a large-scale upper trough over the Great Lakes
and the remnant tropical system moving east across KY/TN will likely
maintain lift through the evening and perhaps into the early morning
hours.

One possibility is that storms along the VA/DE outflow boundary
persist, and translate south across eastern VA where the air mass
remains strongly unstable. Strong wind gusts or hail would be
possible. The more isolated cells across western VA/NC may also
persist with a threat of localized strong wind gusts or hail. 

Additional watches may not be necessary this evening as isolated
cells remain widely spaced over a large area. However, if sufficient
outflow mergers can occur, upscale growth and increasing wind threat
could warrant a watch given the strong instability in place.

..Jewell/Guyer.. 08/28/2020

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

ATTN...WFO...PHI...AKQ...LWX...RAH...RNK...RLX...GSP...MRX...

LAT...LON   35947912 35727979 35798149 36248201 36908202 38068106
            38388042 38977871 38697761 38837644 38807550 38597498
            38037501 37177563 36837627 35947912 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1620.html