First Significant Lake-Effect Snow Event Will Continue Into This Weekend in Great Lakes Snowbelts

Brian Donegan
Published: November 10, 2018

The season's coldest air so far is plunging into the Great Lakes region into this weekend, setting the stage for lake-effect snow in the typical downwind snowbelts.

Lake-effect snow continues to the east and southeast of Lake Superior and Lake Michigan and will increase east of Lake Erie and Lake Ontario through Saturday.

(INTERACTIVE: Winter Radar, Alerts)


Current Winter Radar

As of early Saturday, Gile, Wisconsin, reported 21.6 inches of snowfall and Ironwood, Michigan measured 17 inches.

When sufficiently cold air moves over the relatively warmer waters of the Great Lakes from late fall into winter, it can trigger the formation of localized bands of snow. The snowfall can be heavy at times and contributes to hazardous travel conditions.

(MORE: What Is Lake-Effect Snow?)

Temperatures about 5,000 feet above the surface will drop to 10 to 14 degrees Fahrenheit by late Friday or Saturday, with water temperatures in the Great Lakes still in the 40s to about 50. When the temperature difference between that air aloft and the lake surface reaches at least 23 degrees, it can set the stage for bands of lake-effect snow. This weekend, the temperature difference is expected to well exceed that 23-degree threshold.

The Lake Superior snowbands could produce significant accumulations into Saturday, with lighter amounts in the Lake Michigan snowbelts east of that lake. Gusty winds are also anticipated which will limit visibility.

Winter storm warnings have been issued by the National Weather Service for portions of northern Michigan and northern Wisconsin where heavier snow is expected and travel will be very difficult. 

Snow should taper off by late Saturday as high pressure nudges into the region.

Farther east, organized bands of snow will continue east of lakes Ontario and Erie through Saturday, where conditions will be very favorable for lake-effect snow with well-aligned westerly winds and enough atmospheric moisture to support heavier snow. It will be the first significant snowfall of the season in those snowbelts.

The most persistent lake-effect snowbands Saturday should dump notable snow accumulations over central New York's Tug Hill Plateau due east of Lake Ontario and over the hills and ridges of southwestern New York and northwestern Pennsylvania due east of Lake Erie. This will likely include Erie, Pennsylvania.

Winter storm warnings and winter weather advisories have been posted for portions of western New York where the combination of snow and gusty winds will reduce visibility.


Saturday's Forecast

The National Weather Service office in Buffalo noted that lightning could potentially be associated with the Lake Ontario snowband on Saturday and that thundersnow was already reported on Friday night.

Winds might shift toward a more northwesterly direction Saturday night, which would shift the lake-effect snowbands southeast of lakes Ontario and Erie, causing them to weaken. This could bring the first accumulating snow of the season to Syracuse, New York, if the Lake Ontario band makes it far enough southward.

Lake-effect snow might persist into Sunday southeast of Lake Ontario, potentially including the Syracuse area once again, depending on the exact wind direction.

As high pressure builds to the south this weekend, the other Great Lakes will likely be shut down from producing additional lake snow. However, more snow is expected in the western Great Lakes by Sunday as a new border-riding disturbance arrives from the west.

The heaviest snowfall totals from this weekend's lake-effect event are expected to the south and southeast of Lake Superior and east of lakes Ontario and Erie. The most persistent snowbands will likely produce more than 6 inches of accumulation.


Lake-Effect Snow Forecast Friday Through Sunday

Lake-effect snow is very localized, so if you must drive through one of the lake snowbelts this weekend, be prepared for rapid changes in weather conditions over a very short distance. Snow may fall at 2 to 3 inches per hour at times.

With very cold air expected to be in place into next week, there will be more chances for lake-effect snow in the western Great Lakes early in the week, spreading to the eastern Great Lakes by midweek.


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