Mesoscale Discussion 1719
   NWS Storm Prediction Center Norman OK
   0825 PM CDT Wed Sep 08 2021

   Areas affected...Eastern PA...Northern NJ...Southern
   NY...Northwestern CT...Western MA

   Concerning...Severe Thunderstorm Watch 491...

   Valid 090125Z - 090300Z

   The severe weather threat for Severe Thunderstorm Watch 491
   continues.

   SUMMARY...Severe threat continues with storms this evening.

   DISCUSSION...Broken line of strong/severe convection continues to
   advance east at roughly 25kt. This activity is supported aloft by
   strengthening mid-level flow ahead of Great Lakes/OH Valley upper
   trough. Wind profiles continue to favor organized line
   segments/bow-type structures, the primary concern being with line
   segments oriented more north-south/perpendicular to the mean flow.
   One such feature has formed over south-central PA and is tracking
   east-northeast into western York County. If this storm maintains its
   current track/movement, it will approach southwestern portions of
   ww491 around 0330z.

   ..Darrow.. 09/09/2021

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

   ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...

   LAT...LON   40187644 42477414 42477258 40187492 40187644