Storm Prediction Center Mesoscale Discussion 686

   Mesoscale Discussion 0686
   NWS Storm Prediction Center Norman OK
   0612 PM CDT Sun May 04 2025

   Areas affected...Western PA...northern WV...western MD

   Concerning...Severe potential...Watch unlikely 

   Valid 042312Z - 050115Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Isolated strong to severe storms may continue through the
   evening.

   DISCUSSION...Several cells have recently intensified within an arc
   of convection extending from northern WV into western PA, in the
   vicinity of a low-level confluence zone. This convection is likely
   being aided by an embedded midlevel vorticity maximum moving
   northward around the periphery of the mid/upper cyclone over the
   OH/TN Valleys. Modest heating and cool temperatures aloft have
   allowed for MLCAPE to increase to the 500-1000 J/kg range, within a
   modestly sheared environment. 

   Occasional organized cells will remain possible this evening, posing
   a localized threat of hail and strong wind gusts. A favorable
   overlap of low-level instability and vorticity could also result in
   brief tornado potential, before nocturnal cooling/stabilization
   commences later tonight.

   ..Dean/Smith.. 05/04/2025

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

   ATTN...WFO...CTP...LWX...PBZ...RLX...

   LAT...LON   41108002 39388036 38848047 38718042 38747995 39177929
               39347907 39697861 40237844 41067879 41237917 41247951
               41108002 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN