Winter storms to sweep across U.S.: Al Roker tracks forecast

Two winter storms will bring snow, freezing rain and Arctic cold in a one-two punch to parts of the United States this week.

Some 29 million people were under winter alerts across the central Plains, the Midwest, the Ohio Valley and the mid-Atlantic on Monday morning ahead of two winter storms expected this week.

The first storm will take shape across the central Plains, with rain and light icing across Oklahoma and Arkansas. Come Tuesday, the storm will produce moderate snow from Kentucky to Maryland.

The mid-Atlantic will feel the biggest snow totals with 3 to 6 inches possible. Locally higher amounts of up to 8 inches can’t be ruled out. Washington, D.C., and Baltimore are forecast to pick up 4 to 6 inches of snow with a glaze of ice, Philadelphia could see 2 to 3 inches and New York City around 1 inch.

The southern side of the storm system will see heavy rain possible Tuesday and Wednesday across the South. There, 1 to 3 inches of rain, with locally higher amounts, is possible through Thursday.

The National Weather Service's Weather Prediction Center has issued a slight risk of excessive rainfall over parts of the southern Plains and the lower Mississippi Valley from Tuesday into Wednesday morning because of possible localized flooding. Cities to watch for possible urban flooding include Shreveport, Louisiana; Jackson, Mississippi; Birmingham, Alabama; Atlanta; Knoxville, Tennessee; and Asheville, North Carolina.

The storm will also see Arctic cold air bring temperatures 25 to 40 degrees below average across the northern Rockies and the northern high Plains.

The weather service office in Boulder, Colorado, said “the main chunk of arctic air” arrives Wednesday, and will leave temperature highs in the teens. Meanwhile, the weather service office in Bismarck, North Dakota, said life-threatening wind chills as low as minus 55 degrees Fahrenheit are forecast Monday night into Tuesday morning.

The second storm will start with light snow Tuesday night across Colorado, Nebraska and Kansas. By Wednesday, it'll produce moderate to heavy snow from Kansas to Michigan, with accumulating snow possible for the major metro areas of Kansas City, Missouri; Des Moines, Iowa; Chicago; Milwaukee and Detroit.

In Chicago, the heaviest snow is forecast to fall during the Wednesday evening commute. While it’s too soon to predict how much snow will fall in the Windy City, “comparing the four models, we get anywhere between 4 and 8 inches of snow,” NBC Chicago meteorologist Alicia Roman said.