Widespread, Significant Lake-Effect Snow in Forecast Late This Week

Brian Donegan
Published: December 7,2016
Arctic air has invaded the Lower-48 states, setting the stage for lake-effect snow showers and squalls to affect locations downwind of the Great Lakes through late Friday night.
An upper-level low-pressure system has set up in southern Canada, spinning bitterly cold west to northwest winds over the relatively warmer Great Lakes.
(MORE: Coldest Air of Season Possible Next Week for Midwest, Northeast)

For lake-effect snow to develop, the air temperature about 5,000 feet above the surface must be at least 23 degrees Fahrenheit (13 degrees Celsius) colder than the lake temperature.
The temperatures of the Great Lakes are currently in the 40s, and this arctic air mass will be more than cold enough to irritate the mild lakes.
In fact, lake temperatures are running warmer than they have at this time each of the last five years, according to NOAA's Great Lakes Environmental Research Laboratory.
The cold, dry air will pick up moisture and heat from the lakes, which will condense into clouds and dump snow downwind of the lakes.
(MORE: The Science Behind Lake-Effect Snow)
Some localized, intense snow bands may form, especially off Lakes Erie and Ontario, due to an upwind connection with the upper Great Lakes and possibly even the Hudson Bay at times.

Various lake-effect snow warnings, winter storm warnings and advisories have been posted by the National Weather Service in the typical areas that are prone to lake-effect snow, from Upper Michigan to western Lower Michigan and areas east and southeast of Lakes Erie and Ontario.

Winter Weather Alerts

Due to the extremely localized nature of lake-effect snow, some places could pick up 1 to 3 inches of snow in an hour or less, while just 10 miles away there may only be flurries and some breaks of sun.
In locations that see the most persistent heavy snow bands, total accumulations of 1 to 3 feet are not out of the question east and southeast of Lakes Erie and Ontario. A foot or more of snow could also fall in parts of Upper Michigan and northwest Lower Michigan.

Snowfall Forecast

(FORECAST: Syracuse, New York | Buffalo, New York | Erie, Pennsylvania | Traverse City, Michigan)
As is typical in situations like this, blinding snow squalls can create very poor travel conditions in a matter of minutes. In past winters, we've seen bands of lake-effect snow contribute to multi-car pileups. Please travel with caution in the Great Lakes region through Friday night.
(MORE: Weather-Related Car Accidents Far More Deadly Than Tornadoes, Hurricanes, Floods)
Any steadier bands of lake-effect snow should diminish by Saturday, but a new weather system may bring a more widespread area of snow to the Great Lakes and Northeast Sunday into Monday.
(MORE: Winter Storm Caly Forecast)
Be sure to check back frequently with weather.com for updates on this busy weather pattern.

MORE: Winter Storm Argos