It’s Thanksgiving week, one of the busiest travel times of the year. Weather forecasters said that a series of storms sweeping across the country may disrupt travel plans, with heavy rain and mountain snow expected in the days before the holiday.

Blizzard warnings are in effect for 13 million people and cover parts of northern Wisconsin and the Upper Peninsula of Michigan, and areas east of lakes Erie and Ontario are under lake-effect snow warnings. Significant snowfall has begun, and blizzard conditions are developing as cold air pours in behind the system.

According to FOX 5 NY's Mike Woods, showers will intensify into the evening commute, especially across New York City and areas north and west, before tapering overnight.

Another Arctic blast is on the move toward the U.S., bringing the potential for bitter cold and heavy snow accumulations to parts of New York.

Des Moines, Iowa Madison, Wisconsin and Grand Rapids, Michigan are within the storm's current projected path of heavy snow. The heavy snow is likely to come close to the Chicago area. A northward shift in the storm's track could result in heavy snow in Minneapolis, rather than just a nuisance snowfall.

For the holiday, lake-effect snow is likely to develop downwind of the Great Lakes. “Those traveling on Thanksgiving Day around the Great Lakes region may have to contend with typical lake-effect snow showers, which can result in reduced visibility and slippery travel,” Duff said.

A high-impact storm that will stretch from the Rockies to the Great Lakes this weekend, bringing heavy snow, ice and severe weather to more than a dozen states — and major travel disruptions.

Blizzard warnings were in effect in parts of the upper Midwest on Wednesday as a winter storm continued to churn eastward across the region, dumping heavy snowfall that forecasters warned could snarl Thanksgiving plans.