Mesoscale Discussion 1393
   NWS Storm Prediction Center Norman OK
   0545 AM CDT Tue Aug 04 2020

   Areas affected...Much of New Jersey...southern New York...southern
   New England

   Concerning...Severe potential...Tornado Watch likely 

   Valid 041045Z - 041315Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Conditions will become more favorable for tornadoes this
   morning from New Jersey into parts of southern New England.

   DISCUSSION...A prominent arc of storms which have a history of
   tornadoes continues to move northward across the Delmarva.
   Supporting the threat of tornadoes is strong pressure falls, a very
   moist air mass, and 0-1 SRH in excess of 300 m2/s2. 

   Extending north from the tropical storm Isaias, a quasi-stationary
   zone of rain and storms persists from the PA/NJ border into southern
   NY and western CT. East of this area, dewpoints are well into the
   70s F, resulting in MLCAPE in excess of 500 J/kg as of 11Z.

   As the cyclone continues north, strengthening easterly surface winds
   will allow the instability gradient to shift a bit further inland,
   while shear increases. Further destabilization is possible,
   especially if there can be pockets of heating.

   While isolated cells, including mini-supercells, will be possible,
   the greatest threat for supercells and a few tornadoes is expected
   to remain with the primary, long-lived arcing band of storms, just
   ahead of the cyclone and where pressure falls are strongest.

   ..Jewell/Grams.. 08/04/2020

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

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

   LAT...LON   40277387 39787399 39467419 39297439 39187486 39387551
               39687569 40517544 41427473 41897412 42137344 42177261
               42027210 41887177 41337168 41017184 40727264 40567321
               40477374 40277387