Storm Prediction Center Mesoscale Discussion 820

   Mesoscale Discussion 0820
   NWS Storm Prediction Center Norman OK
   0314 PM CDT Fri May 16 2025

   Areas affected...western/central PA to northern VA

   Concerning...Severe Thunderstorm Watch 263...

   Valid 162014Z - 162215Z

   The severe weather threat for Severe Thunderstorm Watch 263
   continues.

   SUMMARY...A mix of damaging winds and severe hail remains possible
   through early evening from western to central Pennsylvania southward
   into northern Virginia. A corridor of greater damaging wind
   potential is apparent in central Maryland, the District of Columbia,
   and far northern Virginia.

   DISCUSSION...Thunderstorm coverage has steadily increased ahead of a
   minor MCV, and separately along a wavy outflow boundary. Measured
   strong to severe wind gusts have occurred along the outflow
   associated with the MCV. Very strong mid-level winds persist in the
   wake of this MCV, as sampled by recent RLX VWP data. With surface
   temperatures in the mid to upper 80s ahead of this outflow, yielding
   peak MLCAPE of 2000-2500 J/kg, damaging wind swaths are most
   probable into central MD to far northern VA. Farther north,
   convection has largely struggled, outside of a slow-moving supercell
   along the separate outflow boundary in south-central PA. Mixed
   severe hail and damaging wind will remain possible here, amid weak
   low-level shear/SRH.

   ..Grams.. 05/16/2025

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

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

   LAT...LON   41077947 41107851 41097790 40777722 39657638 38947630
               38457635 38177670 38587811 39107820 39617826 40137886
               40727947 41077947 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN