As Thanksgiving travelers began their journeys, snow and cold temperatures have already made an appearance, and more is anticipated throughout the holiday weekend. Much of the northern United States is under winter storm warnings as of Saturday.

The National Weather Service has issued storm warnings and advisories stretching from Montana to New York. Snowfall was predicted to begin on Friday and persist into the weekend, with Iowa and Illinois particularly affected. West-central Illinois is expected to receive between six inches (15 cm) to over a foot (30 cm) of snow from Friday night through Saturday night.

Meteorologists reported that current conditions do not yet qualify for a blizzard warning, which requires winds of at least 35 mph (56 kph), visibility of less than a quarter mile (400 meters), and these conditions lasting more than three hours.

The storm, which had already delivered snow to parts of the northern Plains and the Great Lakes, continued its trajectory on Friday. Snowfall could surpass a foot in certain areas, notably downwind of Lake Superior in Michigan’s northern Lower Peninsula, and near lakes Erie and Ontario. Central New York is also expected to receive up to a foot (30 cm) of snow.

Significant snowfall, exceeding a foot (30 cm), is predicted for portions of Iowa, Illinois, Wisconsin, and Michigan on Saturday, according to the weather service.

The weather service also cautioned that snow squalls on Friday might create short but intense bursts of heavy snow, leading to hazardous whiteout conditions for drivers across the interior Northeast. Their winter storm severity index highlighted the risk of extremely perilous driving conditions in eastern Iowa and northwestern Illinois from Friday afternoon through midnight.

In the Pacific Northwest and the Rockies, a combination of snow and rain was expected Friday. By Saturday, the snow will taper off for the Rockies and northern Plains, but continue on to the Midwest.

To the south, storms — some of them heavy — are in the forecast, with some flash flooding possible Saturday in the western Gulf Coast.

Temperatures were well below average in the eastern and central parts of the country, with highs Friday expected in the 20s degrees F and 30s degrees F in the Midwest, the 30s and 40s in New England and Mid-Atlantic areas, and the 40s and 50s in the Southeast.

The snowy weather on Thanksgiving brought a number of vehicle crashes in western Michigan.