The frigid temperatures of earlier this week are expected to return with a vengeance by Thursday night across a wide swath of Alaska, bringing the coldest weather of the year.
Forecasters say Anchorage could see temperatures down to 20 below by early Friday morning. Other parts of the southern mainland could get colder: Willow and Talkeetna down to minus 30, as well as Western Alaska villages like Aniak and Sleetmute, according to the National Weather Service.
Interior residents are the subject of a weather warning, too, despite the generally colder winter weather in that part of the state. Forecasters issued a special weather statement Wednesday for several inches of snow from McGrath to Fort Yukon — and temperatures falling into the “30s to 50s below” for central and eastern Interior on Friday into Saturday.
Last winter didn’t get below minus 2 in Anchorage, forecasters say. The winter before, however, the mercury dropped to minus 15. The lowest temperature recorded in recent winters belongs to 2008-09, when Anchorage got to minus 24.
A cold snap began over the weekend with temperatures dipping below zero in Anchorage by Sunday evening and below minus 20 in the Susitna Valley. The frigid air backed off by Wednesday morning, with temperatures rising to relatively balmy — though still below average — single digits in places.
But a mass of Arctic air coming down from the north will bring temperatures back down to well below zero by week’s end, according to NWS meteorologist Bill Ludwig.
Anchorage could expect temperatures down to 10 below Wednesday night, with a few places on the east side getting colder, Ludwig said. By Thursday night into Friday morning, the mercury could drop as low as 20 below at the weather service’s gauge at Ted Stevens Anchorage International Airport, with colder readings in some parts of town.
Parts of the Susitna Valley were expected to see temperatures lower than minus 20 Wednesday night, and minus 30 Thursday night into Friday, Ludwig said.
The Weather Service on Wednesday morning also issued a special weather statement warning of “aufeis” or overflow on rivers and streams around Anchorage, the Matanuska Valley and the Kenai Peninsula.
The phenomenon accompanies the ice buildup that comes with the cold snap, according to meteorologist Michael Kutz. Cold air settles in low areas like creek bottoms. As ice thickens in the middle of a channel, water moves toward the banks and oozes up.
“It would be the same if you walked on the ice or drove on the ice,” Kutz said. “Any additional pressure on the ice forces the water to the sides, to the weaker points.”
Things should warm up by the weekend, forecasters say, with some clouds rolling in and temperatures rising into the 20s.
Meanwhile, the forecast is for snow in Southeast Alaska.
The NWS office in Juneau has issued a winter weather advisory as forecasters predict 10 to 15 inches of snow between early Thursday morning and 9 p.m. Friday.
If the forecast holds up, it would be Juneau’s biggest snowstorm since Nov. 18, 2015, when 10 inches of snow was reported at the capital city’s airport, according to weather service records.
If snow falls at the high end of the forecast, it could be the city’s biggest snowstorm since Nov. 29, 2006, when 19.1 inches of snowfall fell in a single day.