Why is it so cold? Seacoast sees coldest start to December in decades

The Seacoast of New Hampshire and Maine is experiencing the coldest start to December in decades, according to the National Weather Service of Gray, Maine.

From Dec. 8 – 9, Portsmouth hit a low temperature of just 8 degrees, while many other parts of New Hampshire and Maine saw subzero temperatures.

“To find one that was this cold through the first eight or nine days of the month, you’ve got to go back to 1989,” said Michael Clair, a meteorologist at NWS Gray. “Portland this morning was down to -3, and that was the first negative reading this early since 1989. Yeah, so by many accounts, it’s been 36 years since we’ve seen similar conditions.”

It’s supposed to warm up briefly Dec. 10 before cooling off again later this week and next.

Why is it so cold?

The cold on the Seacoast is part of a broad pattern across North America, Clair explained.

He said that there’s a “ridge,” or an area of high atmospheric pressure, to the West, which is pumping the warmth up through the western part of the US. To balance that out, there’s a “trough” on other side sending cold air into the Midwest and Northeast.

Another reason for the cold is the snowpack.

“The fact that we got snow last week helps make it colder now, especially at night time,” Clair said. “So those two factors combined are kind of maximizing the potential for cold that we’re seeing.”

The cold isn’t breaking records yet though –  Clair said that 1989 was still much colder than this year.

How cold is it going to be on the Seacoast?

After another cold day Dec. 9, the Seacoast is set to warm up to highs in the 40s Dec. 10.

But it will cool back down after that, Clair said. Thursday through the weekend will see colder than average temperatures: in the teens at night and the 20s to low 30s during the day.

It’s may cool down even more early next week, but Clair said it will depend on a possible system late this weekend.

Will it snow on the Seacoast?

Some snow is expected on the morning of Dec. 10, but it is expected to change to rain.

Any accumulation on the Seacoast will probably get washed away by the rain, Clair said. But the mountains in New Hampshire and Maine may see several inches of accumulation, according to the forecaster’s discussion.

This article originally appeared on Portsmouth Herald. Reporting by Margie Cullen.