Mesoscale Discussion 0973
   NWS Storm Prediction Center Norman OK
   0541 PM CDT Mon Jun 14 2021

   Areas affected...Northern Virginia into Maryland and Delaware

   Concerning...Severe potential...Watch likely 

   Valid 142241Z - 150045Z

   Probability of Watch Issuance...80 percent

   SUMMARY...The environment ahead of an approaching cold front is
   supportive for strong to severe thunderstorms across northern
   Virginia, eastern Maryland, and Delaware. Storms along, and possibly
   ahead of the front will pose a risk for severe hail and damaging
   wind into the evening hours.

   DISCUSSION...Strong convection continues to develop along a cold
   front across southern PA into northern WV, resulting in a few wind
   damage reports as they move to the east. Ahead of this front across
   northern VA and MD, temperatures in the 80s and low 90s with
   dewpoints in the 60s are supporting 1000-1500 J/kg MLCAPE with
   minimal inhibition per RAP mesoanalysis estimates. Additionally,
   strong upper-level flow over the region is supporting 40-50 knots of
   effective bulk shear, which will help organize any convection that
   develops in this thermodynamic environment. 

   Thunderstorms will likely move into the northern VA region by 00 UTC
   along the front, but convective development ahead of the front
   within a subtle lee trough (where a growing field of cumulus is
   noted in recent GOES imagery) is possible in the coming hours. Shear
   vectors oriented nearly along the front should support semi-discrete
   to linear clusters that will pose a hail and damaging wind risk.
   While there is some uncertainty regarding the exact timing of storm
   arrival and the potential for increasing MLCIN after 01 UTC with the
   onset of diurnal cooling, the environment should generally remain
   supportive of a severe risk into the evening hours. A watch will
   likely be needed to cover this threat.

   ..Moore/Guyer.. 06/14/2021

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

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

   LAT...LON   38557889 39097795 39457739 39747686 39967608 39817514
               39127509 38317535 37977597 37887654 37957706 38027767
               38207894 38557889