Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
336 AM EST Sat Nov 19 2022

Valid 12Z Sat Nov 19 2022 - 12Z Tue Nov 22 2022

...Eastern Great Lakes...
Days 1-2...

Single band LES off Lakes Erie and Ontario will continue slowly
lifting northward on gradually backing flow ahead of the main
upper trough axis today before quickly shifting south this evening
with a cold frontal passage. The LES mode turns to multi-band
tonight in NWly flow which persists/slowly veers westerly through
Sunday night. Strong CAA will continue to bring the saturated
layer through the DGZ over lake temps around 50F (~10C) per buoys
in Erie/Ontario. Extreme lake-induced instability and high
inversion heights will continue to support potential for lightning
within the most intense snow bands.

A surface ridge shifts east over the Eastern Great Lakes Sunday
night, which finally brings an end to this prolonged event. Snow
probs through tonight for an additional 6 or more inches are high
around Buffalo and Watertown for the ongoing bands lifting north
today as well as along the Erie Shore from northeastern Ohio
(northeast Cleveland suburbs) through Erie, PA and southwestern
New York. Day 2 snow probs are high for 6 or more inches over the
Tug Hill on westerly flow bands.

Local storm totals may reach 72" in areas just south of Buffalo.

...Western Great Lakes...
Day 1...

The cold front associated with the main upper trough axis moves
through Lake Superior this morning and Lake Michigan this
afternoon.  Upper Lakes tonight and early Saturday will cross Lake
Superior late tonight and Lake Michigan Saturday. A burst of snow
associated with the FROPA will transition to multi-band LES snows
behind the front that continues into tonight (through tonight for
the eastern U.P.).  Day 1 probabilities for at least 6 inches of
snow are moderately high (70-80%) over the western and eastern U.P
and much of the western coast of Lower Michigan. The surface ridge
axis crosses from west to east tonight, shutting off lingering LES
Sunday morning.


Key Messages for Lake Effect Snow in the Great Lakes:

--Periods of heavy lake effect snow will persist through tonight
downwind of Lakes Superior and Michigan and through Sunday night
downwind of Lakes Erie and Ontario.

--East of Lakes Erie and Ontario, heavy snow lifting north today
will shift back south tonight, though generally south of the
heaviest band that persisted through Friday. Snowfall rates of 2-3
in/hr and combine with gusty winds to produce near-zero visibility
and dangerous travel.

--Across parts of the Upper Peninsula and western Lower Peninsula
of Michigan, snowfall rates will again reach 1-2 in/hr this
afternoon and evening behind a cold front and combine with gusty
winds to produce near-zero visibility and dangerous travel.

--Total snow amounts of 1-2 feet are expected in many locations,
reaching 2-3 feet east of Lakes Erie and Ontario. Historic
snowfall exceeding 5 feet has occurred around Buffalo, NY.

--Near zero wind chills are expected after the cold frontal
passage tonight into Sunday.

Jackson