Storm Prediction Center Mesoscale Discussion 1653

   Mesoscale Discussion 1653
   NWS Storm Prediction Center Norman OK
   0135 PM CDT Tue Jul 16 2024

   Areas affected...Eastern Pennsylvania into Northern Maryland...New
   Jersey...and far Southern New York

   Concerning...Severe potential...Watch possible 

   Valid 161835Z - 162030Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A severe thunderstorm watch may be needed later this
   afternoon for storms capable of 60-70 MPH wind gusts.

   DISCUSSION...Visible satellite trends and short-term WoFS guidance
   suggests that thunderstorm activity should increase over Central and
   Eastern Pennsylvania this afternoon, bringing a threat primarily for
   damaging straight-line winds. These storms are expected to progress
   eastward into New Jersey and far southern New York. 

   Surface observations show a hot, dry boundary-layer in place over
   the highlight area, with surface temperatures in the upper 90s F to
   low 100s F and dewpoints in the upper 60s F to low 70s F. These
   conditions have resulted in MLLCL heights of around 2-3 km and
   low-level lapse rates that are dry adiabatic beneath the LCL.
   Additionally, the better deep-layer wind shear supportive of
   organized convection is confined to northern and central PA,
   suggesting that the primary threat is for damaging winds from
   disorganized to weakly-organized multi-cell clusters. Weather watch
   issuance may be needed later this afternoon.

   ..Halbert/Squitieri/Hart.. 07/16/2024

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

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

   LAT...LON   39917808 41057765 41307728 41407675 41497604 41447524
               41337454 41317399 41137362 40797362 40517369 39977409
               39837432 39687500 39557577 39277620 38967647 38807661
               38727693 38707737 38817799 39117826 39567818 39917808