Mesoscale Discussion 1487
   NWS Storm Prediction Center Norman OK
   0855 AM CDT Sun Jun 30 2024

   Areas affected...portions of the Mid-Atlantic and southern New
   England

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 301355Z - 301600Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Thunderstorm coverage will gradually increase in
   coverage/intensity through midday. Swaths of damaging wind gusts are
   expected through afternoon. One or more severe thunderstorm watches
   will likely be needed in the next couple of hours for portions of
   the Mid-Atlantic into New England.

   DISCUSSION...A very moist airmass is already in place across the
   region this morning, with surface dewpoints in the low to mid 70s F
   noted in observations. Temperatures are already in the upper 70s to
   low 80s, and even modest heating through broken clouds will aid in
   further destabilization toward midday. 12z RAOBs from ALB and OKX
   also indicate a strongly sheared environment, with effective shear
   magnitudes greater than 40 kt present. Early convection is already
   noted near Binghamton NY along an outflow boundary. Additional
   convection is developing further west across central PA ahead of an
   east/southeast-advancing cold front.

   As convection gradually increases over the next few hours, bowing
   segments/clusters are expected given mostly unidirectional
   deep-layer flow. Large instability, high PW values, and steepening
   low-level lapse rates amid favorable shear will support swaths of
   damaging winds across the region through the afternoon into early
   evening. One or more watches will likely be needed for the region
   within the next couple of hours.

   ..Leitman/Gleason.. 06/30/2024

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

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

   LAT...LON   42087612 42887429 43017286 42997153 42917079 42557045
               41937050 41627060 40257239 39747343 39197460 39307544
               39417600 39867669 40327696 40717692 41487664 42087612