Mesoscale Discussion Issued for a Large Part of Our Area...

 

Mesoscale Discussion 1632

   NWS Storm Prediction Center Norman OK

   0256 PM CDT Sat Aug 29 2020

   Areas affected...Portions of central/eastern PA...northern/central

   NJ...and southern NY

   Concerning...Severe potential...Watch unlikely 

   Valid 291956Z - 292200Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Isolated strong to damaging winds may occur with storms as

   they move eastward this afternoon. Watch issuance appears unlikely

   at this time.

   DISCUSSION...Showers and low-topped thunderstorms have formed over

   the past couple of hours along a surface trough extending southward

   across central PA. Poor mid-level lapse rates observed on the 12Z

   PIT sounding and related weak instability (MLCAPE generally 500-1000

   J/kg) have limited updraft strength so far this afternoon. Even so,

   there appears to be a window for storms to modestly strengthen over

   the next couple of hours as they move eastward into central PA and

   parts of NJ, where continued diurnal heating is acting to modestly

   steepen low-level lapse rates. Strengthening low/mid-level westerly

   winds associated with an approaching upper trough are evident in the

   VWP from KCCX. Some potential may exist for isolated strong/gusty

   downdraft winds to produce occasional damage with any of the

   stronger cores that can develop through the remainder of the

   afternoon. At this point, overall convective coverage and intensity

   will probably remain too isolated/marginal to justify watch

   issuance.

   ..Gleason/Grams.. 08/29/2020

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

   ATTN...WFO...OKX...PHI...BGM...CTP...

   LAT...LON   40387752 41527676 41757528 41487409 40437436 39747593

               39737687 40387752