Mesoscale Discussion 1348
   NWS Storm Prediction Center Norman OK
   0535 PM CDT Thu Jun 20 2024

   Areas affected...much of Massachusetts and adjacent southern New
   Hampshire

   Concerning...Severe Thunderstorm Watch 438...

   Valid 202235Z - 210030Z

   The severe weather threat for Severe Thunderstorm Watch 438
   continues.

   SUMMARY...A developing cluster of thunderstorms may still pose
   increasing risk of producing damaging wind gusts while spreading
   southeastward across Massachusetts, perhaps including much of the
   Greater Boston vicinity, by 8-9 PM EDT.

   DISCUSSION...The boundary layer remains strongly heated (including
   surface temperatures near 90F) and characterized by seasonably high
   moisture content supportive of mixed-layer CAPE in excess of 2000
   J/kg, along pre-frontal surface troughing inland of the southern New
   England coast.  This is beneath prominent mid/upper ridging, but
   north of the ridge axis, where deep-layer westerly mean flow may be
   on the order of 15-20 kt.  Aided by southerly low-level inflow of
   the unstable air, strengthening ongoing storms along a corridor
   southeast of Albany NY into the Keene NH vicinity may still undergo
   further intensification and upscale growth during the next hour or
   two.  As this occurs, consolidating southeastward propagating
   outflow may be accompanied by increasing risk for potentially
   damaging wind gusts into the 00-01Z time frame.

   ..Kerr.. 06/20/2024

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

   ATTN...WFO...GYX...BOX...ALY...

   LAT...LON   42427332 42777227 42807188 42827119 42117069 42037161
               41987249 42077327 42427332