North Dakota remained under a wind chill advisory Tuesday, but forecasters expected the mercury to climb above zero.

The warmup, even if slight, was welcomed after the wind chill factor hit minus 50 in parts of the state Monday.

Airman 1st Class Matthew Bolin, a weather technician at Grand Forks Air Force Base, said crew members were full of questions about wind chill temperatures. The base logged a wind chill factor of 51 below, he said.

"We actually suspended all outdoor activity here on the base," he said. "We have a formula for calculating the wind chill, and any time we record it at minus 47, we issue that final warning."

The American Automobile Association club reported a long waiting list of stranded drivers Monday. Service stations and tow truck operators were busy as temperatures, even without the wind chill factor, dipped to nearly 25 below in the northern part of the state.

Bismarck's Ace Towing had to send a crew to the Burnt Creek boat dock to pull out a car that had broken through the ice a day earlier.

"The guys out there are chilly," owner George Kuntz said.

"I hate it," said Terry Renecker, a trucker from the Fargo area. "My air brakes froze."

A trucker from Canada, Terry Anderson, was idling his vehicle to keep the fuel from freezing.

"It can create trouble if you're not prepared," he said.

Residents were advised to dress for the cold - layering sweaters and wearing gloves and hats - to guard against frostbite.

Highs Tuesday were expected from zero to 10 above, but a wind chill advisory was in effect through noon. Forecasters said wind chills could hit around 30 below.

Lows Tuesday night were expected from 5 to 15 below. But changes in an upper level low pressure system will bring a warmup to the 20s later in the week, forecasters said.

"After Wednesday, that low is going to break down and we're going to get milder Pacific air moving in," said meteorologist Bill Abeling, at the National Weather Service in Bismarck.