Raleigh, N.C. — The coldest air of the season arrived in the Triangle Tuesday, setting up a week of frigid temperatures that could bring one of the coldest nights in years, WRAL Chief Meteorologist Greg Fishel said. 

Highs Tuesday didn't climb out of the 30s, and a northwesterly wind that gusted between 15 and 20 mph kept wind chills in the 20s for much of the day despite abundant sunshine.  More Info     Protecting homes, cars and pets in cold weather

Temperatures dropped below freezing after the sun went down and were expected to plummet into the low 20s and upper teens overnight.

"We're all on our way to very cold night as temperatures drop down into the 20s," Chief Meteorologist Greg Fishel said.

The Raleigh Rescue Mission on Hargett Street was at capacity Tuesday night as the homeless sought shelter from the bitter cold.

"The extreme cold amplifies things. Obviously, it's a matter sometimes of life or death," said Lynn Daniell, director of the Raleigh Rescue Mission. "Particularly when it gets down to the upper teens like we're seeing for the night."

As of 10 p.m., it was 20 degrees colder in Raleigh than it was at the same time Monday night.

Frigid air that moved into the U.S. from Canada over the weekend caused dramatic temperature drops in the Ohio Valley and Great Lakes, with wind chills well below 0 degrees early Tuesday morning in several states.

"Our temperatures are going to be the big story really for the week," said WRAL meteorologist Elizabeth Gardner. "Everyone is going to have to deal with it."

Highs will climb into the low 40s on Wednesday, and back into the high 30s Thursday and Friday, but even a gradual warm-up won't get daytime highs to late January averages.