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ACUS11 KWNS 110156
SPC MCD 110155

Mesoscale Discussion 1794
NWS Storm Prediction Center Norman OK
0755 PM CST Sun Dec 10 2017

Areas affected...lee of Lake Erie and Lake Ontario

Concerning...Heavy snow

Valid 110155Z - 110700Z

SUMMARY...Persistent lake effect snow bands extending west-northwest
from Lake Erie and Lake Ontario will persist into the overnight.
Highest snowfall rates from these bands are peaking now (locally in
excess of 2 inches per hour) and should begin to weaken later

DISCUSSION...Lake effect snow bands have persisted through the
afternoon across portions of Erie, Wyoming, Genesee, and Orleans
Counties in western New York and Jefferson, Oswego, Lewis, and
Herkimer Counties across northern New York. Observations suggest
that these bands have intensified over the last few hours and are
producing snowfall rates in excess of 2" per hour, with locally
higher rates likely. Given water temperatures in the mid 30s F, 850
millibar temperatures of -9.5 C (per 00Z BUF sounding), and westerly
low-level flow around 35 knots, these lake effect snow bands will
continue for the next 4-6 hours. In the 06-08Z time frame, a surface
cold front should move through the area resulting in low-level flow
veering. As such, lake effect snow bands will shift south and west,
with an overall weakening trend given the shorter fetch over the

..Marsh/Broyles.. 12/11/2017

...Please see for graphic product...


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