Tim Buckner of MJ Goss Motors plows the sidewalk along Adams Avenue on Tuesday, Dec. 28, 2021. 

LA GRANDE — Thermometer mercury has made quite a journey this year, from heat waves breaking records in June to a cold front bringing a rare snowstorm to Seattle and Portland and chilly temperatures that might break records on New Year’s Eve.

“What is bringing this in is a low-pressure troughing pattern — a series of lows that are originating as continental air masses rather than marine air masses, so we’re getting colder air that is more arctic in nature,” said Colby Goatley, a meteorologist with the National Weather Service in Pendleton.

Goatley said the pattern is more typical, and doesn’t bear the characteristics of a polar vortex. Still, the temperatures will drop significantly overnight.

Nighttime lows for La Grande through New Year’s Day will dip into the single digits, with the lowest temperature predicted to be as low as 4 degrees on Friday, Dec. 31, according to the weather service. The previous record for La Grande was set in 1968 with a nighttime low of minus 3. Daytime highs will hover in the 20s and remain below freezing for the rest of the week.

A high probability of snow through Dec. 31 could accumulate up to 4 inches by Dec. 30, tapering off by New Year’s Day as weather improves.

“If you’re going to be out during those cold temperatures, just make sure you’re plenty bundled up,” Goatley said. “You can get frostbite pretty fast.”

The cold weather will handily beat out last year’s temperatures that kept steady above 18 degrees for December. This is partly due to the La Nina weather pattern returning, bringing more precipitation to the Pacific Northwest.

Goatley cautioned that wind chills could bring the temperatures down even further to the negative teens, though the chance of wind gusts are low. With the cold weather, precautions should be taken by drivers traveling back after the holidays, as well as by owners of livestock or animals who may get caught in the biting cold.

“Make sure any animals have adequate shelter or brought indoors, and pipes are covered to prevent bursting,” he said.

Installing pipe sleeves or simply running water through the night — even just a trickle — can also prevent pipes from bursting, according to the American Red Cross.