Storm Prediction Center Mesoscale Discussion 1654

   Mesoscale Discussion 1654
   NWS Storm Prediction Center Norman OK
   0450 PM CDT Sat Jul 18 2026

   Areas affected...Parts of southern NY and northeast PA into far
   western MA/CT

   Concerning...Severe Thunderstorm Watch 494...

   Valid 182150Z - 182345Z

   The severe weather threat for Severe Thunderstorm Watch 494
   continues.

   SUMMARY...A threat for damaging wind, isolated hail, and possibly a
   tornado will spread across the eastern portion of WW 494. The need
   for downstream watch issuance is uncertain.

   DISCUSSION...A small storm cluster with an embedded supercell north
   of Binghamton is moving east-southeastward as of 2130 UTC. This
   cluster has a history of producing wind damage, while MRMS hail-size
   estimates with the embedded supercell have occasionally exceeded 1
   inch. This cluster will continue to pose a short-term threat of
   damaging wind and perhaps isolated hail in the short term as it
   approaches the eastern extent of WW 494.

   Downstream, earlier convection and persistent cloudiness has limited
   diurnal heating and destabilization, though rich moisture and
   temperatures gradually warming into low/mid 70s F have allowed
   MLCAPE to rise into the 500-1000 J/kg range. With rather strong
   deep-layer shear in place, this modest buoyancy may be sufficient to
   maintain ongoing organized storm structures as they move out of WW
   494. Poor lapse rates may tend to limit the magnitude of the threat
   as storms approach the Hudson Valley, but at least a localized
   wind-damage threat may persist. Also, veering wind profiles and
   favorable low-level SRH (as depicted on the 18Z ALB sounding and
   recent VWPs from KENX) may also support a brief tornado threat
   within the effective warm-frontal zone. 

   The need for downstream watch issuance remains uncertain, and will
   depend on trends regarding ongoing storm intensity/organization and
   downstream destabilization.

   ..Dean/Hart.. 07/18/2026

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

   ATTN...WFO...OKX...ALY...BGM...CTP...

   LAT...LON   42667562 42427392 42297347 42057330 41477306 41167333
               41497463 41877592 41977734 42197756 42667562 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN