Mesoscale Discussion 0599
   NWS Storm Prediction Center Norman OK
   0159 PM CDT Fri May 15 2020

   Areas affected...central into eastern New York...far northeast
   Pennsylvania...western Massachussetts...southern Vermont...southern
   New Hampshire

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

   Valid 151859Z - 152030Z

   Probability of Watch Issuance...95 percent

   SUMMARY...The threat for severe storms will increase through the
   afternoon. Damaging gusts and large hail will be the primary threats
   throughout the Northeast, but storms interacting with a warm front
   may produce a couple tornadoes. A Tornado Watch will be issued soon.

   DISCUSSION...A mid-level shortwave trough and surface low are
   approaching the Northeast U.S from Ontario, and are expected to
   traverse the Upper Hudson Valley/New England areas into the evening
   hours. As such, thunderstorm development and intensification is
   expected throughout the afternoon. While limited low-level moisture
   and modest mid-level lapse rates (evident per special 18Z ALB
   sounding) will limit buoyancy to a degree, 500-1000 J/kg MLCAPE is
   expected to materialize by mid afternoon with continued insolation.
   Stronger mid-level flow accompanying the shortwave trough will
   promote 40-50 knot effective bulks shear values, promoting organized
   storms, including linear segments and transient supercells capable
   of damaging winds and occasional large hail given the aforementioned
   instability. 

   In addition, 925-850 mb flow is expected to increase across portions
   of eastern New York into parts of southern New England through the
   afternoon, enhancing low-level shear to a degree. Locally higher
   streamwise vorticity may also be associated with a warm front draped
   across the region. Storms embedded in the stronger low-level flow
   axis may acquire transient low-level rotation, where a couple of
   tornadoes cannot be ruled out, particularly with storms ingesting
   the higher streamwise vorticity  while traversing the warm front. A
   Tornado Watch will be issued shortly to address these concerns.

   ..Squitieri/Dial.. 05/15/2020

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

   ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF...

   LAT...LON   41527602 41787644 42237695 42767714 43207700 43527660
               44167534 44087458 43877341 43557291 43077248 42637238
               42187243 42027356 41667479 41527602