BETHLEHEM, Pa. - You thought last night was cold?
Bundle up, because the coldest air in two years will spread over the region over the next day or so, according to the National Weather Service.
Temperatures will be almost 20 degrees below normal, with highs in the 20s Sunday and lows Sunday night in the single digits to low teens.
The Lehigh Valley will get to about 24 degrees Sunday then plunge to a frigid low of 5 degrees Sunday night, forecasters said.
It will get warmer and closer to normal as the week progresses.
Straight from the North Pole
For now, though, arctic high pressure centered over Canada and the Great Lakes is moving our way, with the coldest period coming Sunday and overnight Sunday.
The air mass reaching us now was over the frozen Arctic Ocean and North Pole six days ago, the weather service said. In that time it's had little exposure to the sun to warm it as it moves south.
Temperatures combined with a steady northwest breeze near 10 to 15 mph Sunday will result in daytime wind chills only topping out into the teens in spite of bright sunshine, according to the weather service’s forecast discussion.
A cold weather advisory for the Poconos, including Monroe and Carbon counties, remains in effect with wind chills ranging from 10 to 15 degrees below zero.
Winds will taper off later in the day Sunday. While wind chill won’t be a factor, the weather service says the coldest air since the winter of 2021-2022 will move across much of the area.
Forecast lows by daybreak Monday range from near zero in the Poconos to single digits across much of southeastern Pennsylvania. Locally colder temperatures are possible where there’s more snow cover.
Not record territory
While it will be unusually cold, we won’t set any records. Forecast highs are about 5 to 10 degrees shy of records set in December 1989, according to the weather service.
The arctic high pressure will slide away by Monday night but it will remain cold with highs in the 20s to mid 30s. Going through the week, temperatures will be generally below normal and back to normal or slightly above that by the weekend.
Christmas Eve and Christmas Day on Tuesday and Wednesday both look to be partly sunny with highs around 37 or 38, the weather service said. Nighttime lows Tuesday through Thursday will be around 25 degrees.
