Storm Prediction Center Mesoscale Discussion 674

   Mesoscale Discussion 0674
   NWS Storm Prediction Center Norman OK
   0546 PM CDT Sat May 03 2025

   Areas affected...parts of nern MD...nrn DE...sern Pa...wrn/cntrl NJ

   Concerning...Severe Thunderstorm Watch 219...220...

   Valid 032246Z - 032345Z

   The severe weather threat for Severe Thunderstorm Watch 219, 220
   continues.

   SUMMARY...A small organizing cluster of storms may pose increasing
   potential to produce strong to severe surface gusts across the
   Harrisburg PA vicinity into areas near/northwest of Philadelphia
   through 8-9 PM EDT.

   DISCUSSION...Within a modestly heated and well-mixed boundary layer,
   characterized by 20-25+ F surface temperature/dew points spreads and
   CAPE on the order of 500-1000 J/kg, scattered vigorous thunderstorm
   development continues.  This is generally focused within weak
   surface troughing, beneath difluent upper flow across the northern
   Mid Atlantic vicinity.  

   Deep-layer shear is moderately strong beneath 40 kt
   south-southwesterly flow around 500 mb, and this continues to
   support at least one isolated supercell now moving into the Greater
   Philadelphia area, accompanied by potential for marginally severe
   hail and locally strong surface gusts.

   Upstream, convection has consolidated into a small organizing
   cluster to the north and northwest of the Greater Washington
   D.C./Baltimore metro area.  This activity could still pose
   increasing potential to produce produce strong to severe surface
   gusts while propagating across the Harrisburg vicinity and areas
   near/northwest of the Greater Philadelphia area through 00-01Z.

   ..Kerr.. 05/03/2025

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

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

   LAT...LON   40167690 40597569 40697461 40237443 39777494 39587568
               39097704 39557705 40167690 

   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN