Mesoscale Discussion 0062
   NWS Storm Prediction Center Norman OK
   0251 AM CST Thu Jan 31 2019

   Areas affected...Lee of Lake Ontario (southern Jefferson...northern
   Oswego...and Lewis Counties)

   Concerning...Heavy snow 

   Valid 310851Z - 311445Z

   SUMMARY...High snowfall rates (2"+/hr) are expected within a single
   snow band in lee of Lake Ontario through the remainder of the night
   and this morning.  This snow band will shift southward through 12Z
   and should stall near and south of the Jefferson/Oswego Counties
   line into northern Oswego and southern Lewis Counties through at
   least the morning.

   DISCUSSION...Trends in mosaic radar and individual radar imagery
   indicated a southward shift of a lake effect snow band over and in
   lee of Lake Ontario has been underway since about 07Z.  Surface
   observation along the north shore of the lake at CWQP (Point Petre,
   ON) showed the wind had veered to westerly with the equatorward
   passage of this band.  The passage of a surface trough across
   southern ON and far southern QB, while the northern extent of an
   anticyclone expands into the lower Great Lakes through this morning,
   should maintain a westerly long-fetch convective snow band across
   the long axis and in lee of Lake Ontario.  Most CAMs suggest the
   southward shift of the band will persist through 12Z across southern
   Jefferson and northern Lewis Counties.  General agreement then
   exists indicating the band will stall near and south of the
   Jefferson/Oswego Counties line into northern Oswego to southern
   Lewis Counties through the morning.

   Steep low-level lapse rates per forecast soundings and persistent
   low-level convergence across the long axis of Lake Ontario suggest
   high snowfall rates in lee of the eastern part of this lake, while
   upslope flow inland will further enhance these snowfall rates.

   ..Peters.. 01/31/2019

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

   ATTN...WFO...BGM...BUF...

   LAT...LON   43847633 43847583 43757535 43567524 43417546 43337576
               43427627 43457651 43647629 43847633