ZCZC SPCSWOMCD ALL
ACUS11 KWNS 150356 
SPC MCD 150356 
NYZ000-151000-

Mesoscale Discussion 1883
NWS Storm Prediction Center Norman OK
0956 PM CST Wed Dec 14 2016

Areas affected...Portions of northern New York...Lake Ontario

Concerning...Heavy snow 

Valid 150356Z - 151000Z

SUMMARY...The primary lake-effect snow plume is expected to slowly
move southward and reorient to more of an east-west configuration
overnight. 2-4 inch-per-hour rates will continue to be possible,
along with a few lightning strikes.

DISCUSSION...At 0345Z, an intense lake-effect snow band is slowly
drifting southward across Lake Ontario and adjacent portions of
upstate New York. Very cold temperatures aloft are resulting in
steep lapse rates and modest buoyancy over the lake (SBCAPE of
100-200 J/kg per recent mesoanalysis), with CG lightning recently
noted over portions of Jefferson and Lewis counties. Substantial
cooling aloft will continue into the overnight hours, with 700 mb
temps eventually dropping below -30C. This cooling will enhance the
available buoyancy and maintain the potential for very heavy rates
and occasional lightning strikes. 

As the very cold vortex over northern Ontario moves eastward
overnight, some veering of the flow is expected, which may reorient
the main band somewhat to more of a west-east configuration and
result in a longer fetch off of Lake Ontario, which will further
enhance the potential for very heavy snow rates. Rates of 2-3 inches
per hour will be common, with locally higher rates possible within
the strongest convective elements.

..Dean/Edwards.. 12/15/2016

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

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

LAT...LON   43327765 43467824 43737780 43947646 44267471 44057444
            43637455 43377602 43267714 43327765 

NNNN