Storm Prediction Center Mesoscale Discussion 2263

   Mesoscale Discussion 2263
   NWS Storm Prediction Center Norman OK
   1121 AM CST Thu Dec 12 2024

   Areas affected...coastal Lake Ontario in western New York

   Concerning...Heavy snow 

   Valid 121721Z - 122115Z

   SUMMARY...Heavy snow, with rates approaching 2 inches/hr, may
   accompany the ongoing snow band across eastern Lake Ontario through
   the early to mid afternoon hours.

   DISCUSSION...A lake effect snowband is in progress across the
   eastern shore of Lake Ontario, with periods of at least moderate
   snowfall rates noted via surface observations. 17Z mesoanalysis
   shows deep-layer flow fields oriented roughly parallel to the lake
   axis, supporting a long fetch of onshore moisture. Continued diurnal
   heating, however weak, is encouraging 8 C/km boundary-layer lapse
   rates given cooling aloft, and this may support convective snowfall
   into the afternoon hours. While mostly 1 inch/hr snowfall rates are
   likely, a couple instances of 2 inch/hr rates may occur.

   ..Squitieri.. 12/12/2024

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

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

   LAT...LON   44127627 44247564 44287493 44177465 43927510 43867553
               43857581 43887614 43917624 44127627