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Mesoscale Discussion 490
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MD 490 graphic

   Mesoscale Discussion 0490
   NWS Storm Prediction Center Norman OK
   1252 PM CDT Tue May 22 2018

   Areas affected...Northeastern Virginia...southern Maryland...and the
   District of Columbia

   Concerning...Severe potential...Watch possible 

   Valid 221752Z - 221945Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Damaging wind gusts will be possible with stronger storms
   this afternoon.

   DISCUSSION...A relatively cloud-free area on visible satellite
   imagery has been persistent throughout the morning into early
   afternoon. This has allowed surface temperatures to rise into the
   mid- to upper-70s. With ample surface moisture -- dewpoints
   generally in the mid- to upper-60s -- MLCAPE values are currently
   near 1000 J/kg. With time, continued surface heating should further
   destabilize the area. Shear values are relatively modest with values
   between 25-30 kts; however, particularly in areas that receive the
   most insolation, low-level lapse rates may support damaging wind
   gusts. Visible satellite imagery indicates weak convection occurring
   to the west of the discussion area. These storms should intensify as
   they move into a move favorable environment east of the

   ..Wendt/Elliott/Weiss.. 05/22/2018

   ...Please see for graphic product...


   LAT...LON   38317897 38907871 39117819 39107730 38697638 38207605
               37767622 37587652 37237696 37197806 37427907 37707924

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