Mesoscale Discussion 1139
   NWS Storm Prediction Center Norman OK
   1201 PM CDT Wed Jul 08 2020

   Areas affected...Portions of eastern New York into Vermont...New
   Hampshire...western and central Maine...northern Massachusetts

   Concerning...Severe potential...Watch possible 

   Valid 081701Z - 081900Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Storms are expected to gradually increase in coverage and
   intensify throughout the afternoon. The stronger storms will be
   capable of producing damaging gusts, and a couple instances of
   severe hail cannot be ruled out.

   DISCUSSION...Diurnal heating has gradually destabilized the boundary
   layer through Noon, as evident in visible satellite with a growing
   CU field and temperatures reaching into the 80s F, with upper
   60s/near 70 F dewpoints based on latest METAR observations. Visible
   satellite and mosaic MRMS reflectivity data indicate convection has
   initiated along a baroclinic zone across far southern Quebec, and
   these storms are expected to cross into New England and gradually
   intensify during the early-mid afternoon hours. More isolated storms
   are also slowly developing ahead of the aforementioned band of
   convection across New England, with intensification expected with
   continued heating, as also suggested by the 12Z HREF, last several
   runs of the HRRR, and other high-resolution deterministic guidance.

   The near upper 60s dewpoints and continued insolation should foster
   modest buoyancy, with up to near 2000 J/kg MLCAPE expected by mid
   afternoon per 15Z RAP forecast soundings. While overall tropospheric
   winds will be relatively weak, strong enough flow aloft is expected
   to contribute up to 30 knots of effective bulk shear, with modest
   veering in the lowest 2 km, resulting in small, clockwise curved
   hodographs. Multicellular storm mode is expected, with a couple of
   transient supercell structures also possible. Damaging gusts are
   expected to be the main threat, with a couple instances of severe
   hail and perhaps a brief instance of low-level rotation unable to be
   completely ruled out.

   ..Squitieri/Guyer.. 07/08/2020

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

   ATTN...WFO...CAR...GYX...BOX...BTV...ALY...

   LAT...LON   43247471 44147430 45057335 45027138 45817048 45956974
               45616950 44746924 44226914 43666995 43097054 42747086
               42587178 42577243 42817383 43247471