Mesoscale Discussion 1320
   NWS Storm Prediction Center Norman OK
   0317 PM CDT Tue Jul 20 2021

   Areas affected...Parts of western through much of northern New York
   State and adjacent northern Vermont

   Concerning...Severe Thunderstorm Watch 384...

   Valid 202017Z - 202215Z

   The severe weather threat for Severe Thunderstorm Watch 384
   continues.

   SUMMARY...An organized cluster of thunderstorms will spread across
   the St. Lawrence River through much of the Adirondacks vicinity,
   along with continuing development across and southeast of Lake
   Ontario by 5-7 PM EDT, accompanied by the risk for potentially
   damaging wind gusts.

   DISCUSSION...Moderate southeasterly low-level inflow of moist air
   characterized by CAPE in excess of 1000 J/kg is maintaining vigorous
   thunderstorm development along the leading edge of an
   east-southeastward advancing, convectively driven surface cold pool.
    This continues to be aided by large-scale forcing for ascent
   associated with a 30-50 kt westerly mid/upper jet streak, and will
   overspread the upper St. Lawrence Valley through much of the
   Adirondacks region by 22-23Z.  As the temperature gradient across
   the gust front increases at least a bit further, potential for
   damaging wind gusts probably will also continue to increase during
   the next hour or two.

   Farther to the southwest, thunderstorms which initiated along the
   trailing outflow boundary, and preceding lake breezes across the
   Lake Ontario vicinity, may also begin to consolidate while spreading
   into the unstable environment to the southeast of the lake.  This
   too may gradually pose increasing risk for damaging wind gusts
   near/north of the Finger Lakes region through the Mohawk Valley by
   early evening.

   ..Kerr.. 07/20/2021

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

   ATTN...WFO...BTV...ALY...BGM...BUF...

   LAT...LON   43997686 44397609 44977514 45277421 44887322 43647392
               43047508 42957641 43187737 43627813 43997686