Tuesday, July 14, 2026

Mesoscale Discussion 1614 ... Watch Possible!

This builds on what I said in the earlier post!



Storm Prediction Center MD 1613



Mesoscale Discussion 1613
   NWS Storm Prediction Center Norman OK
   0115 PM CDT Tue Jul 14 2026

   Areas affected...parts  of western Maine...northern New Hampshire
   and Vermont

   Concerning...Severe potential...Watch possible 

   Valid 141815Z - 142015Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Severe thunderstorm development appears increasingly
   probable across the St. Lawrence Valley through the western New
   England international border vicinity by 4-6 PM EDT.  These may be
   accompanied by large hail and potential to produce tornadoes, in
   addition to damaging wind gusts.

   DISCUSSION...A mesoscale convective vortex has progressed across the
   international border and will continue east-south east of the
   Greenville ME vicinity toward Downeast coastal areas this afternoon.
     Thunderstorm activity near the vortex has been steadily
   dissipating for several hours now, but renewed thunderstorm
   development persists along (and to the cool side of) an associated
   outflow boundary trailing west-northwestward across southwestern
   Quebec.  

   Some of this upstream activity has shown recent signs of
   intensification, mainly near and to the west of the St. Lawrence
   Valley, where inflow may be emanating from a moist boundary-layer
   with surface dew points near 70F.  Still mostly beneath a plume of
   warm and capping elevated mixed-layer air, this air appears
   characterized by CAPE in excess of 2000 J/kg.

   Through 20-22Z, model output suggests that the elevated mixed-layer
   plume will slowly become suppressed southward across southern Quebec
   through the international border vicinity.  As it does, there
   appears increasing potential for scattered thunderstorms to continue
   intensifying along and, perhaps, across the outflow boundary,
   becoming increasingly rooted in the unstable boundary-layer.  In the
   presence of strong deep-layer shear, a few supercell structures may
   evolve, accompanied by a risk for large hail, damaging wind gusts
   and potential for a tornado or two while spreading into and across
   the international border vicinity.

   ..Kerr/Hart.. 07/14/2026

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

   ATTN...WFO...CAR...GYX...BTV...

   LAT...LON   46007068 45476945 44846913 44367070 45877459 47037437
               47087288 46007068 

   MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN