Mesoscale Discussion 1417
   NWS Storm Prediction Center Norman OK
   1230 PM CDT Fri Aug 07 2020

   Areas affected...South-central/southeast PA...MD...DC...Eastern WV
   Panhandle...Northern VA/DE...Southwest NJ

   Concerning...Severe potential...Watch unlikely 

   Valid 071730Z - 072000Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Strong thunderstorms are possible this afternoon, with a
   few potentially becoming severe. WW issuance is unlikely at this
   time.

   DISCUSSION...At 1730Z, thunderstorms are gradually increasing in
   coverage and intensity across central/southern PA, in advance of a
   weak midlevel shortwave trough. Downstream heating noted near and
   south of a nearly stationary surface boundary will allow MLCAPE to
   increase into the 1500-2000 J/kg range, which will promote continued
   intensification of ongoing updrafts along with new convective
   development later this afternoon. Low-level flow should remain
   generally weak, but modestly enhanced mid/upper-level southwesterly
   flow will result in effective shear of 25-35 kt across the region,
   supporting some storm organization. Multicell clusters are expected
   to be the dominant storm mode, though some weak supercell
   development will be possible, especially near and just north of the
   surface boundary, which may sag southward with time as convective
   coverage increases. 

   Locally damaging wind will be possible, especially where greater
   heating and steepening of low-level lapse rates can occur. Weak
   midlevel lapse rates should generally limit the hail risk, though
   marginally severe hail cannot be entirely ruled out if any supercell
   structures can be maintained. At this time, the magnitude and
   coverage of the severe threat appear too limited for watch issuance.

   ..Dean/Kerr.. 08/07/2020

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

   ATTN...WFO...PHI...CTP...LWX...

   LAT...LON   40177769 40617751 40827736 40917687 40937674 40767618
               40407561 39937495 39367532 39177560 38897605 38547674
               38847833 39217847 39527839 40177769