The National Weather Service warned that severe winter conditions—triggered by an Arctic blast—could persist over the weekend into Monday.

Biting cold conditions – below-freezing in some areas – will sweep across a large swath of the United States Sunday while heavy, record-breaking lake-effect snow makes post-holiday travel “treacherous” and nearly “impossible” in parts of the Great Lakes region.

The National Weather Service has issued a series of winter weather advisories across the country as an estimated 80 million Americans are expected to travel at least 50 miles from their homes to celebrate Thanksgiving tomorrow.

Mother Nature is about to serve up some unappetizing conditions for the millions of Thanksgiving travelers: sloppy weather, snow, the coldest temperatures since February and a potentially disruptive storm are on the way through the holiday weekend. Here’s a day-by-day look at what to expect this week.

Winter storm warnings are in effect from eastern New York through central and northern New England, with over a foot of fresh snow possible, forecasters said.