Storm Prediction Center Mesoscale Discussion 1687

   Mesoscale Discussion 1687
   NWS Storm Prediction Center Norman OK
   0935 AM CDT Tue Jul 21 2026

   Areas affected...northern New Jersey into southeast New York and
   southwest Connecticut

   Concerning...Severe potential...Watch unlikely 

   Valid 211435Z - 211600Z

   Probability of Watch Issuance...20 percent

   SUMMARY...A localized severe weather threat is expected this morning
   across northeast New Jersey, southeast New York, and southwest
   Connecticut.

   DISCUSSION...A supercell has developed along a warm front in
   northern New Jersey this morning. This supercell should continue
   east along the warm front through the morning with some large hail
   and damaging wind threat. In addition, stronger southeasterly flow
   off the Atlantic may lead to some greater low-level shear and
   tornado potential, especially right along the warm front. Therefore,
   some tornado threat may also exist with this cell as it continues
   east.  The overall threat is somewhat muted at this time by the
   relatively weak instability, but mid 70s dewpoints are advecting
   northeastward quickly and will continue to destabilize the airmass
   south of this front. Therefore, this cell and any additional cells
   which develop along the front will be monitored closely this
   morning, but the limited instability should mitigate the need for a
   watch.

   ..Bentley/Mosier.. 07/21/2026

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

   ATTN...WFO...OKX...PHI...

   LAT...LON   41247344 41147296 40957293 40787310 40717364 40747428
               41037426 41207413 41247344 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN