Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 212019
SWOMCD
SPC MCD 212019
VAZ000-MDZ000-NCZ000-DCZ000-WVZ000-TNZ000-SCZ000-212115-

Mesoscale Discussion 0539
NWS Storm Prediction Center Norman OK
0319 PM CDT Fri Apr 21 2017

Areas affected...Northern and western North Carolina...far
northeastern Tennessee...far southern West Virginia...much of
Virginia...portions of southern Maryland...and the District of
Columbia

Concerning...Severe potential...Watch unlikely

Valid 212019Z - 212115Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated to scattered convection will persist in the
region through the early evening, with a downward trend in intensity
expected after dark.  A WW is not anticipated for this activity.

DISCUSSION...Isolated thunderstorms continue to move eastward at
approximately 25-30 knots across the region.  These storms were in
an environment characterized by relatively modest deep shear (around
25-35 knots) and relatively weak instability (500-1250 J/kg MUCAPE).
The deep shear is relatively marginal for well organized storms,
although a few instances of damaging wind gusts may occur with the
strongest activity owing to steep low-level lapse rates.  Hail
approaching 1" in diameter may also occur.  Low-level boundaries
near northern Virginia/southern Maryland may locally enhance updraft
intensity and attendant severe threat, although this threat is
expected to be brief.  Storms should diminish in intensity after
dark with loss of solar heating.

Given the marginal and isolated nature of the severe threat, a WW
issuance is not anticipated for this activity.

..Cook/Goss.. 04/21/2017

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

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

LAT...LON   39347672 39297727 39027798 38567885 38307976 37938090
            37448186 36608255 36108284 35578305 35288287 35148219
            35538034 35917841 36147723 36277670 36787647 37317638
            38107630 38787641 39067648 39347672



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