Storm Prediction Center Mesoscale Discussion 1666

   Mesoscale Discussion 1666
   NWS Storm Prediction Center Norman OK
   1127 AM CDT Wed Jul 17 2024

   Areas affected...Eastern PA/northern NJ into western New England

   Concerning...Severe potential...Watch likely 

   Valid 171627Z - 171830Z

   Probability of Watch Issuance...80 percent

   SUMMARY...The damaging-wind threat will increase this afternoon. One
   or more watches will likely be needed.

   DISCUSSION...Relatively strong heating is underway from parts of the
   Mid Atlantic into western New England, to the east of an extensive
   cloud shield that is moving eastward across western/central NY/PA
   and WV. A seasonably deep upper-level trough will move eastward
   across the lower Great Lakes and Northeast through the day, while an
   MCV embedded in the larger-scale trough will move from WV toward the
   Mid Atlantic. Cumulus is gradually building from east-central PA
   into southeast NY, and a general increasing in storm development and
   coverage is expected with time this afternoon. 

   Midlevel lapse rates are weak (as noted on regional 12Z soundings),
   but continued heating will support MLCAPE increasing above 1000 J/kg
   with time. Modestly enhanced midlevel flow will support 30-40 kt of
   effective shear, sufficient for some storm organization. Multiple
   storm clusters and possibly a couple of supercells may evolve with
   time, with steepening low-level lapse rates supporting a primary
   threat of damaging wind. Some threat for isolated hail and/or a
   brief tornado is also possible if any supercells can be sustained.
   One or more watches will likely be needed this afternoon to cover
   the damaging-wind threat.

   ..Dean/Hart.. 07/17/2024

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

   ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP...
   LWX...

   LAT...LON   40317389 39737510 39527769 39867743 41267620 42887433
               43587327 43697258 43467206 42067273 40317389