Raleigh, N.C. — An arctic air mass is expected to remain in place across North Carolina through the workweek with daytime highs in the 30s and lows in the teens to lower 20s.

"We had 32 for a high on Saturday and Sunday, while Monday's high was 36 degrees," WRAL meteorologist Mike Maze said.

Tuesday is expected to be sunny with a high of 36 and a low of 21.

Wednesday will reach into the 30s, and a slight warm-up Thursday could send the mercury all the way to the low 40s before crashing into the mid 20s again that night.

The warm, moist air might hang around long enough to meet up with a new blast of cold air. If that happens, we do have the potential for snow Thursday evening, Maze said.

"The atmosphere will be cold enough to support snow, so we are not concerned about any wintry mix or freezing rain or sleet," Maze explained.

The snowfall would be a brief event without much precipitation, Maze said.

Friday morning would be partly cloudy and cold.

Cold freezing water lines

Everyone is urged to prepare for the unusually cold weather such as checking heating units and protecting exposed water pipes.

Plumber Mike Waite, with Cary Plumbing, said the cold spell is keeping him busy repairing busted water pipes. Among the causes are unprotected irrigation backflow valves.

“(Irrigation) pipes burst all the time when they're not protected. A lot of people forget to take them out in the winter months when they're not using the irrigation systems. And if you leave a pipe exposed to freezing weather, it's going to burst,” Waite explained.

Waite said nearly every problem plumbers respond to during the winter months can be prevented.

“Leaving outside faucets attached to their hose bib, we replace more of those than anything else,” he said.

Measures such as removing hoses from the spigot, closing crawl space vents, eliminating drafts of cold air and insulating exposed pipes can help prevent costly repairs.

“For a three-quarter inch, you've got to have 1 inch all the way around of foam insulation. Anything less than that will allow it to freeze,” Waite said.

Additional ways to weather-guard water pipes is to keep inside faucets running at a slow drip and to leave cabinets near sinks open so warmer air can circulate.