Storm Prediction Center Mesoscale Discussion 2209

   Mesoscale Discussion 2209
   NWS Storm Prediction Center Norman OK
   0748 PM CDT Wed Sep 02 2026

   Areas affected...northern PA vicinity

   Concerning...Severe Thunderstorm Watch 646...

   Valid 030048Z - 030215Z

   The severe weather threat for Severe Thunderstorm Watch 646
   continues.

   SUMMARY...Severe potential will continue over the next few hours
   across northern PA.

   DISCUSSION...The main severe hazard will continue to be damaging
   wind gusts and hail with more discrete convection across
   north-central PA in the short term. VWP data from KCCX indicates
   somewhat small but favorably curved low-level hodographs and 0-1 km
   SRH greater than 150 m2/s2. Given the very moist and unstable
   airmass in place, a tornado can not be ruled out, but damaging wind
   and hail are expected to be the primary hazards, especially as loss
   of daytime heating results in gradual low-level stabilization. The
   southern extent of a line moving across western NY will spread into
   portions of northern PA over the next 30-60 minutes. This activity
   could pose a greater risk for damaging gusts given the
   well-organized line and storm motion around 40 kt.

   Downstream across eastern PA, the thermodynamic environment quickly
   becomes more hostile for sustained severe potential. A sharp
   instability gradient and rapidly increasing inhibition should limit
   the eastward extent of severe potential, and a downstream watch is
   not expected.

   ..Leitman.. 09/03/2026

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

   ATTN...WFO...BGM...BUF...CTP...PBZ...CLE...

   LAT...LON   41817586 41627584 41237594 40907625 40667709 40857928
               41368089 41548096 42108091 42328033 41977893 42027717
               41957605 41817586 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN