As brutal cold sets in across the United States, the Gulf Coast braces for a rare winter storm

An intense blast of arctic air is sweeping across much of the United States to start the week, following a storm system off the East Coast that dumped snow on the mid-Atlantic and the northeast over the weekend. But as these areas shake off the snow, a rare and significant winter storm will threaten the Gulf Coast states and the Southeast starting Monday evening.

The frigid air mass is affecting the western, central and eastern United States this week, causing temperatures to drop well below normal for January. High temperatures on Monday are expected to be 20 to 30 degrees colder than average.

In the Northern Plains and Upper Midwest, temperatures are expected to be in the low 10s or single digits. The Rockies, Central Plains and Midwest will likely see temperatures in the single digits into the teens, while the East Coast, New England and Mid-Atlantic are bracing for temperatures in the teens and 20s.

The snowstorm that moved across the Northeast and Mid-Atlantic on Sunday left behind some of the largest snow accumulations of the season. Grantsville, Maryland, just south of the Pennsylvania border, recorded 13.5 inches. In New York, the largest totals were in the southeastern part of the state, north of New York City, with about eight inches in Fahnestock State Park, Highland Mills and Hopewell Junction. Central Park recorded 1.6 inches.

In Washington, D.C., which received just under an inch of snow on Sunday, organizers of President-elect Donald J. Trump’s inauguration moved the inauguration ceremony indoors for the first time since 1985. “British cold is expected” Monday, the National Weather Service said, warning that temperatures ranging from the teens to the twenties were likely, with gusts up to 30 mph likely bringing wind chills down to single digits and in below from zero.