Lake-effect snow to unleash whiteouts, snarl post-Thanksgiving travel

An extreme lake-effect snow event will begin over the extended holiday weekend with near-blizzard conditions threatening to shut down highways and bury towns with feet of snow.

As Arctic air blasts across the Great Lakes region in the wake of a late-November snow and rainstorm, a tremendous natural snowmaking machine will be turned on high and will encompass much of the extended Thanksgiving holiday weekend and into early next week, AccuWeather meteorologists advise.

Local conditions can vary tremendously from one mile to the next, ranging from non-accumulating flurries to a complete whiteout. The heavy rate of snow and the likelihood of blowing and drifting snow could strand some motorists on the roads, especially long-distance travelers with little to no experience with lake-effect snow.

Road crews may struggle to keep up with the snow in some areas, which can be complicated by heavy traffic during the Thanksgiving holiday.

“We expect snowfall rates of 2-3 inches per hour and locally more intense, which can close roads such as interstates 79, 81, 86 and 90 to name a few in the eastern Great Lakes,” AccuWeather Chief Meteorologist Jonathon Porter said, “Multiple feet of snow will pile up in the most persistent snow bands.”

Along with the rapid accumulation of snow in the heaviest bands and blizzardlike conditions, visibility can drop to near zero, adding to the risk of multiple-vehicle pile-ups and perhaps causing some motorists to lose their way and drift off the road.

“This air mass coming in is much different than the conditions during the big snowstorm from last week in the Northeast and recent prior events in the Upper Midwest,” AccuWeather Chief On-Air Meteorologist Bernie Rayno said, “This cold air outbreak will bring much lower temperatures and allow road surfaces to quickly cool and the snow to accumulate.”

Road conditions will quickly transition from wet to slushy to snow-covered with icy spots.

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The predominately west-to-northwest wind will direct the bands of heavy snow to western and northern Michigan, northern Wisconsin, northwestern Indiana, northwestern Pennsylvania, northeastern Ohio and portions of western and northern New York.

“While there is some risk of a heavy snow band shifting into Buffalo, New York, briefly, most of the time, winds will be from the west and northwest and will direct the heaviest snow from the towns south of Buffalo to western New York’s ski country,” AccuWeather Meteorologist Grady Gilman said.

Another zone where feet of snow can pile up quickly will be just east of Lake Ontario in northern New York, known as the Tug Hill Plateau region.

The difference in temperature between the air and the waters of the Great Lakes produces lake-effect. The greater the temperature extreme, the more intense the snow can be. The Great Lakes, as a whole, are close to or slightly above the warmest they have ever been on this date, eclipsing the previous warmest year, 2016, AccuWeather Meteorologist Brandon Buckingham said.

“With water temperatures of all of the lakes except for Superior still averaging in the lower to middle 50s Fahrenheit and the air blowing over the lakes expected to be in the teens, 20s and lower 30s, towering clouds will form and align in streets or bands that produce heavy snow,” Buckingham explained, “Thunder and lightning can occur in the most intense bands with strong wind gusts.”

Looking ahead, the pattern is expected to be favorable for rounds of snow across the Great Lakes region beyond early next week.

“The pattern will favor storms from Canada (Alberta clippers) to sweep through the Great Lakes region with their own snow, but then a period of lake-effect snow will follow each clipper storm into mid-December,” Buckingham said.

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