BUFFALO, N.Y. — A multi-day, significant lake-effect snowstorm is under way around the Great Lakes, working to bury towns along the eastern shores with multiple feet of snow into next week.

As a potent low pressure system moves out of the Northeast on Thanksgiving, the coldest air of the season chased the storm out of Canada and is sweeping across the Great Lakes, which are currently experiencing record-warm water temperatures.

"This is going to be a long-fused event," NWS Buffalo lead forecaster Kirk Apffel told FOX Weather. "We're looking for Friday through at least Monday, there's going to be snow in the area."

Over 2.4 million are now under a Lake-Effect Snow Warning through at least Monday across parts of western New York, far northwestern Pennsylvania and northeastern Ohio as Lake Erie and Lake Ontario crank up the snow-making machine. A variety of Winter Storm Warnings and Winter Weather Advisories cover prone areas of Michigan.

More than 23 inches have fallen in Sault Ste. Marie, Michigan through Friday, while more than a foot was reported in Northeast Ohio and Northwest Pennsylvania.

Travel restrictions were in place for a significant stretch of Interstate 90, stretching from the Buckeye State to Canada, with many larger vehicles banned from usage.

FOX Weather Exclusive Storm Tracker Brandon Copic said even smaller passenger vehicles were having a tough time maneuvering through the snow and rescues were taking place.

How much snow is expected around Buffalo and Watertown?

While current projections keep the heaviest snow just south of Downtown Buffalo, the city has now been upgraded to the Lake Effect Storm Warning, where parts of the city could see 1-2 feet of snow by midweek.

"The greatest snow amounts in the Buffalo Metro area are expected across the nearby Southern Suburbs and possibly South Buffalo," NWS Buffalo forecasters wrote. "Little, or no snow is expected across the Northtowns."

The Lake-Effect Snow Warning also includes Orchard Park, where the Buffalo Bills are scheduled to take on the San Francisco 49ers on Sunday Night Football. Current projections indicate the snow may be falling south of the stadium at game time, but it'll be close, and overall storm totals are expected to eventually reach over a foot there.

Snow forecasts rapidly increase as you head south, reaching 18-24 inches in Hamburg and 3-4 feet in Dunkirk. Central and northern New York cities and towns along Lake Ontario, including Oswego and Watertown, are in the warning as well.

FOX Weather Storm Specialist Mike Seidel was already reporting more than a foot of snow while reporting from Mayville, New York.

"We’re talking (the snow began) 9 1/2 hours ago, and we’re up to almost a foot of snow," Seidel said as snowflakes covered the screen. "So you can do the mathematics, we’re still getting at least 1 inch per hour… and it’s adding up fast because the temperatures are nice and cold (at) 28 degrees. So the fluff factor increases; you get more snow in inches out of an inch of liquid than if it was 32 degrees."

Even farther inland will get heavy snow, with 12-18 inches likely in Pike and 5-8 inches in Warsaw.

Snow forecasts from the FOX Forecast Center show the heaviest amounts off Lake Ontario, with now 3-4 feet of snow in Watertown between Friday and Wednesday, and 4-6 feet in Montague and Cathage.

How much snow is expected near Cleveland and Erie?

Snow forecasts have increased Friday morning as you carry farther south into Erie, Pennsylvania and even northeastern Ohio around Ashtabula where now 3-4 feet may accumulate.

"I was informed that on (Interstate) 79 northbound is quite the mess as well as most of the side roads," said FOX Weather Storm Tracker Brandon Copic as he drove through Erie County late Friday morning. "I've been on a few of the side roads, and it's quickly showing that the snow just keeps piling up and the crews are doing the best that they can. But it's just hard to keep up with all the snow that's falling."

The Cleveland area is under a Winter Weather Advisory for up to 6 inches of snow, mainly in the northeastern suburbs.

Travel disruptions are likely, especially on Interstate 90 between Cleveland and Buffalo and on Interstate 81 north of Syracuse, New York.

WHAT MAKES A LAKE-EFFECT SNOWSTORM?

With water temperatures running 4 to 6.5 degrees above average, the arctic winds pick up the warmth and moisture from the waters and transfer it into the lowest portion of the Earth’s atmosphere.

This rising air condenses into clouds, which can grow into narrow bands that are capable of producing snowfall rates on the order of 2 to 3 inches per hour or more, according to the National Weather Service.

How much snow will fall across Michigan's Upper Peninsula?

Heavy snows are also likely across Michigan’s Upper Peninsula and northwestern Michigan as the chilly winds blow off Lake Superior and northern Lake Michigan. But forecasts have wildly variable snow totals, ranging from 5 inches to as much as 2-3 feet, depending on where snow bands are set up.

"Snow is fluffy but wet," forecasters at the NWS office in Gaylord, Michigan said Friday morning as the snow came down. "If you run into one of these, it will quickly be discombobulating."

"It really a lot of it has to do with the (winds) running down the length of the lake," Apffel said. "And sometimes you have a favored area where it will converge, come together, and that's when you can get some of those most intense bands. And when it's not running down the length of the lake, sometimes things tend to be more disorganized with multiple bands. So it is something that we can forecast, but it is challenging."

The Lake-Effect snow squalls are expected to last through the middle of next week, until another weather system comes along to change the wind direction. Suffice to say, it will be a very wintry week of weather along the Great Lakes.

In addition, the coldest air of the season will sweep across the eastern half of the nation, with around 230 million Americans feeling below-average temperatures into early next week.