Mesoscale Discussion 0324
   NWS Storm Prediction Center Norman OK
   1009 AM CDT Thu Apr 09 2020

   Areas affected...eastern PA/NJ/southeastern NY/eastern MD/the
   DELMARVA Peninsula

   Concerning...Severe potential...Watch possible 

   Valid 091509Z - 091615Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Locally strong/damaging wind gusts are expected as a
   low-topped band of convection intensifies and moves quickly eastward
   across the discussion area over the next few hours.  A WW may be
   required.

   DISCUSSION...Latest radar loop shows a band of frontal convection
   moving eastward across the central Appalachians at this time,
   through an environment that remains only weakly unstable at best,
   per recent RUC-based objective analysis.  This is borne out by the
   dearth of lightning observed with the convection at this time.

   With that said, clearing has occurred east of the mountains from
   eastern PA and parts of NJ southward, in the wake of earlier
   convection which has moved offshore.  Resulting heating, beneath
   steep mid-level lapse rates in conjunction with the mid-level low
   crossing the Lower Great Lakes region and adjacent parts of eastern
   Ontario/western Quebec will allow modest CAPE development through
   the morning and early afternoon.  

   With destabilization likely to permit a gradually more robust band
   of low-topped convection to evolve, background fast/westerly flow
   aloft (increasing to 40 to 50 kt in the 800 to 600 mb layer per the
   morning PIT RAOB) will result in fast storm motions, and potential
   for local downward mixing of the stronger winds to the surface.  We
   will continue to monitor airmass destabilization ahead of the front,
   and corresponding convective evolution, with respect to potential
   need for a severe thunderstorm watch in the next hour or so.

   ..Goss/Guyer.. 04/09/2020

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

   ATTN...WFO...OKX...PHI...BGM...AKQ...CTP...LWX...

   LAT...LON   41327380 40927322 39547389 38187530 38477682 39447682
               40407608 40907557 41337480 41327380