Mesoscale Discussion 0844
   NWS Storm Prediction Center Norman OK
   1246 PM CDT Thu Jun 03 2021

   Areas affected...southern and central Virginia northeastward to
   southeastern Pennsylvania and vicinity

   Concerning...Severe potential...Watch possible 

   Valid 031746Z - 031945Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Locally strong/severe storms are expected to develop this
   afternoon along and east of the higher terrain.  A WW may be
   required.

   DISCUSSION...Latest visible satellite imagery shows a recent
   increase in vertical cumulus growth in the vicinity of the Blue
   Ridge, as rather thin/broken high cloudiness continues to permit
   gradual heating.  While rather weak lapse rates will limit
   destabilization potential to some degree, 500 to 1000 J/kg
   mixed-layer CAPE is now indicated across central and northern
   Virginia.  This will support a continued, gradual increase in
   convective coverage and intensity this afternoon, as large-scale
   ascent ahead of the eastward-moving Ohio Valley trough continues to
   spread across the region.

   Aiding in local convective intensification will be amply strong
   0-6km shear, supported by a belt of mid-level southwesterly flow
   around 40 kt atop the area.  As such, a few multicell
   clusters/bands, and even a couple of storms with mid-level rotation,
   are expected.  This gradual ramp-up in convective coverage/intensity
   -- and associated risk for primarily damaging wind gusts -- will
   likely require some consideration for WW issuance this afternoon.

   ..Goss/Guyer.. 06/03/2021

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

   ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...

   LAT...LON   37567981 37768003 39447818 40337645 40467526 39837503
               38487583 37427661 37077758 37047901 37567981