Snow was falling in the Mid-Atlantic and New York City on Sunday. The coldest air in several years will descend across much of the country starting Monday, forecasters said.

BOSTON (AP) — Residents across the country from the Northern Plains to the tip of Maine are bracing for dangerously low temperatures as tens of millions of residents along the East Coast contend with a thick blanket of snow — and more snowfall in the forecast.

Storm Demi is forecast to bring snow to some of the nation’s largest cities, including Washington D.C., New York, and Boston, on Sunday. The winter storm will also usher in cold temperatures in its wake.