Mesoscale Discussion 1591
   NWS Storm Prediction Center Norman OK
   0841 AM CDT Thu Aug 27 2020

   Areas affected...southern NY

   Concerning...Severe potential...Watch unlikely 

   Valid 271341Z - 271515Z

   Probability of Watch Issuance...20 percent

   SUMMARY...An isolated risk for severe gusts may accompany a small
   thunderstorm cluster as it moves across southern NY this morning. 
   The expectation is the coverage of storms will remain isolated and
   the associated severe threat will not warrant a severe thunderstorm
   watch for the ongoing activity.

   DISCUSSION...Radar mosaic shows a small thunderstorm cluster over
   south-central parts of NY moving quickly east-southeast towards the
   lower Hudson Valley.  Surface temperatures per NY Mesonet data show
   lower 60s immediately ahead of the storms and temperatures rising to
   near 70 near the north exurbia of greater NYC.  The thunderstorms
   are located on the northeastern rim of an elevated mixed layer plume
   pinched between the stronger westerlies over the Great
   Lakes/Northeast and the influence of Hurricane Laura over the lower
   MS Valley.  The 12z Buffalo, NY observed sounding sampled the
   modestly steep mid-level lapse rates with 1300 J/kg MLCAPE.  The 12z
   Albany, NY and the Brookhaven, NY observed soundings showed
   saturated profiles with little CAPE.  However, the Albany and
   Buffalo soundings showed strong to very strong 700mb flow (50-75
   kt).  

   It appears the 00z NSSL-WRF guidance has depicted the ongoing
   activity very well and this model output suggests this small
   thunderstorm cluster will move to the east-southeast and not expand
   in coverage.  Given the observational trends and a seemingly
   reasonable depiction by the model guidance, current thinking is the
   risk for severe will remain isolated during the morning.  However,
   renewed thunderstorm development is expected farther west in lee of
   Lake Ontario/Erie by early afternoon.  The later activity is
   forecast to grow upscale and yield a much more substantial risk for
   severe compared to the ongoing storms.

   ..Smith/Grams.. 08/27/2020

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

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

   LAT...LON   41757313 41297341 41267386 42397552 42607537 42587488
               41757313