Storm Prediction Center Mesoscale Discussion 1260

   Mesoscale Discussion 1260
   NWS Storm Prediction Center Norman OK
   0345 PM CDT Mon Jun 22 2026

   Areas affected...southeast PA into NJ

   Concerning...Severe Thunderstorm Watch 375...

   Valid 222045Z - 222215Z

   The severe weather threat for Severe Thunderstorm Watch 375
   continues.

   SUMMARY...Supercell thunderstorm risk increasing. Damaging winds,
   hail, and possibly a tornado could accompany this activity across
   far southeast Pennsylvania into southern New Jersey over the next
   1-2 hours.

   DISCUSSION...A supercell storm has developed across southeast PA
   this afternoon within a favorably sheared and unstable environment.
   Surface observations indicate potential outflow oriented west to
   east across the area from earlier storms. While the downstream
   airmass itself will support a severe risk, if this supercell can
   maintain organization and interact with this outflow boundary (where
   0-1 km SRH would be enhanced), an increasing risk for a tornado also
   could occur in addition to damaging wind and isolated hail. 

   An additional storm approaching northern DE also will be moving into
   a more favorable airmass supporting strong to damaging wind gusts
   over the next hour.

   ..Leitman.. 06/22/2026

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

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

   LAT...LON   40387566 40357472 40097417 39627405 39407438 39387486
               39437597 39687630 40257601 40387566 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN