Lake-effect to bury some communities under feet of snow

The coldest air of the season so far will unleash a tremendous and long-lasting lake-effect snow event from Michigan and Wisconsin to Pennsylvania, New York and Ohio in the days following Thanksgiving. AccuWeather meteorologists warn that in some areas, the snow will be so intense it could strand motorists and close major highways.

Because the Great Lakes are so warm relative to the cold air pouring in, towering clouds will organize into bands, some only several miles wide.

Within the snow bands, "we expect snowfall rates of 2-3 inches per hour with locally 5 inches per hour, which can close major roads such as interstates 79, 81, 86 and 90, to name a few in the eastern Great Lakes," AccuWeather Chief Meteorologist Jonathan Porter said.

Sections of major highways, such as 75 and I-196 in Michigan, may also close. Road crews may struggle to keep up with the snow in some areas, which can be complicated by heavy traffic during the extended Thanksgiving holiday weekend.

For those who have not experienced lake-effect snow, within the snow bands, blizzard conditions can occur, and feet of snow can pile up where the bands persist. Outside of the snow bands, only flurries or a clear sky are sometimes the case, which can lead to a false sense of security or create dramatically different conditions from one mile to the next when traveling on the highway.

"Should a traveler become stranded, the situation can quickly escalate to a life-threatening emergency given the conditions," Porter warned.

Temperatures may plummet through the 20s and into the teens with AccuWeather RealFeel® Temperatures 15-30 degrees lower, factoring in gusty winds that often accompany the lake effect. Snow could block the exhaust systems of some stranded vehicles, raising the risk of carbon monoxide poisoning to occupants.

"The conditions and impacts are of great concern during the holiday weekend as there may be many people traveling through the impacted areas not as familiar with the intensity and dramatic changes that can occur over short distances with such intense lake-effect snow bands," Porter said.

The predominant wind direction will be from the west-northwest, directing the heaviest snow bands toward some communities but away from others.

Stiff winds can push the snow around, creating whiteout conditions and leading to mountainous drifts that can easily cover vehicles and home entrances.

"While there is some risk of a heavy snow band shifting into the city of Buffalo, New York, briefly, most of the time, winds will direct the heaviest snow from the towns south of Buffalo to western New York's ski country," AccuWeather Meteorologist Grady Gilman said.

Highmark Stadium, located in Orchard Park, New York, is home to the Buffalo Bills football team. The team's next home game is scheduled for Sunday evening, and heavy snow could be a factor for those attempting to get to the event and drive home afterward. Over 12 inches of snow may have already fallen by the scheduled start of the game.

The heaviest snow is still expected to fall later Saturday into early Sunday before the snow bands can shift south of the stadium. A storm total snow accumulation of 1-2 feet is expected in Orchard Park, but the most intense bands nearby to the south along I-90 can produce 2-4 feet of snow through Sunday.

Another hot spot for snow in the eastern Great Lakes region will occur to the east and southeast of Lake Ontario in the zone from Syracuse to Watertown, New York, which includes stretches of I-81 and I-90. This area is referred to as the Tug Hill Plateau region and is notorious for picking up feet of lake-effect snow when winds are from the west and northwest.

The AccuWeather Local StormMax™ snowfall for the entire lake-effect event spanning Thursday night to Tuesday is 72 inches or 6 feet.

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While some of the snow bands can extend for a couple of hundred miles inland of the lake producing the snow, most often little or no snow will reach cities such as Indianapolis, Columbus, Ohio, or the I-95 mega cities near sea level including Washington, D.C., Philadelphia, New York City and Boston.

However, often lake-effect snow bands can survive the trip to the central and northern Appalachians. These higher elevations, especially the west and northwest-facing slopes, can sometimes pick up a few inches of snow. These areas include northern West Virginia, western Maryland, west-central Pennsylvania, northeastern Pennsylvania, southeastern upstate New York, western Massachusetts and even Vermont. Motorists venturing through these areas should anticipate changing conditions, including wintry travel as they venture into the mountains.

The same pattern producing the lake-effect snow will also allow fast-moving storms from western Canada, known as Alberta clippers, to track through part of the East next week.

These storms can not only enhance the snow bands and cause them to shift around but may also bring snow to areas often missed by the lake effect, including areas west of Lake Michigan and along I-70 in the Midwest and along I-95 in the Northeast.

There is sometimes the potential for one of these clipper storms to strengthen quickly and slow down as it reaches the Atlantic coast, where it could bring heavier snowfall. AccuWeather meteorologists will be closely watching for these opportunities next week.

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