Frigid cold will stick around

Make sure your water pipes are protected and your pets have warm shelter. The Triangle is about to get hit by the coldest sustained spell we've experienced in awhile.

So far, the National Weather Service has not put snow in the forecast. But meteorologists are watching for the possibility of snowfall Sunday or early next week, said Brandon Locklear of the National Weather Service's office in Raleigh.

In the meantime, an arctic cold front will move into the Triangle on Thursday afternoon, driving temperatures down to bone-chilling levels and keeping them there through Saturday morning. The overnight low Thursday is expected to be around 15 degrees. And it will be even more frigid Friday night, with a low around 13 degrees.

The region hasn't had temperatures that cold since 2005. And that year, snow on the ground contributed to the glacial temperatures.

This week, the strength of the arctic blast alone will drive down the readings, Locklear said. "This is a very impressive cold air mass coming in," he said.

It's not just the two nights of numbing cold that will have the big impact but the fact that the low temperatures will stay so long, Locklear said.

If we're lucky, temperatures may rise to 28 or 29 degrees on Friday, he said. And even when temperatures climb above freezing on Saturday, the relative warmth won't last long, with another big dip into the mid-20s overnight on Saturday.

With so many hours of deep freeze, the National Weather Service is urging people to take preventive steps to keep exposed pipes from bursting and to make sure pets are protected.

"The story is not one single night but the fact that we may see 48 hours of below-freezing temperatures," Locklear said. "That's where we run into actual problems as far as pipes freezing and bursting."

The temperatures will be so cold for so long, in fact, that some small ponds may freeze over -- a rare event for the region.

Locklear said it's too early to know whether to expect snow before the weekend ends. There are too many unknown variables, he said, and computer models "are all over the place right now."

"If we are going to get something, this will be the right period," he said.