Thursday 21 December 2017

Record warmth AGAIN in Alaska

Baked Alaska: 49th state is having an insanely warm December

20 December, 2017

The National Weather Service recently described Alaska’s weather so far this month as “exceptionally mild.” That might be an understatement.

Freakishly warm conditions, compared to normal, are happening all over the state. The snowpack and sea ice conditions are out of sorts. And people don’t like it.

Fairbanks, Anchorage and Juneau, as well as many remote towns, are having their warmest December on record so far, according to Brian Brettschneider, a climatologist based in Anchorage.

In Fairbanks, temperatures have averaged an incredible 20 degrees above normal. Setting aside Dec. 1, every day has been warmer than normal, often much warmer. Most days have seen highs near 30 and lows near 10. That might sound cold, but the normal high is in the single digits and the normal low around minus-10.

On Dec. 8, Juneau soared to 54 degrees, tying its warmest temperature ever recorded during the month. Three of its 10 highest December temperatures on record came that week, the Juneau Empire reported. “It was warmer in Juneau … than it was in Houston,” the newspaper wrote. “That’s the Houston in Texas, not the one in Southcentral Alaska.”

During the middle of the month, Anchorage saw its temperature climb to at least 45 degrees on four straight days, a record span for December. It also tied its warmest winter day on record, Dec. 11, with an average temperature of 41.5 degrees. The low temperature that day of 37 degrees matched the warmest of any winter month in history.

More-remote Alaska outposts have also witnessed historically warm conditions. The average temperature in Eagle, Alaska, near the Canadian border, is running 23.5 degrees above normal so far, Brettschneider said. On Dec. 14, Bettles, in north central Alaska, and Kotzebue, along the west coast, tied monthly record highs of 38 and 37 degrees.

In a place so brutally cold, one might think this mild weather is welcome. No so, Brettschneider says. “People do not like the warm temperatures,” he said in an email. “It makes things very icy when the temperatures get above freezing. Since the ground is frozen several inches thick, snow melting on the surface freezes to the ground (or road). Because the sun is so low, it does not melt the ice directly. Ice can hang around for weeks and even months.”

While warm weather turns snow into a treacherous sheet of ice on the ground, it melts ice on Alaska’s rivers or prevents it from forming, taking away an important travel option. “Many of those critical travel corridors are shut down,” Brettschneider said. “Imagine shutting down the Interstate highway connecting Key West from Miami.”
View image on Twitter
Bering Sea ice extent from the high resolution multi-sensor@NSIDC MASIE database as of Dec 16th is 2nd lowest (since 2006). Analysis from @NWSAlaska. For longer context, 2017 also 2nd lowest in the lower-res passive mircowave (since 1978).   @Climatologist49 @ZLabe

In addition, sea ice, important for protecting vulnerable coastlines from wave action during storms, is near-record low levels in the Bering Sea, Brettschneider noted.

The warm weather pattern over the state dates back months. In Utqiaġvik, Alaska, previously known as Barrow, 74 of the last 79 days have been warmer than normal, going back to Oct. 1.

For the state as a whole, warmer-than-normal days have outnumbered the cold 3 to 1 since April.

Weather forecasting models suggest the remainder of December will also be abnormally warm. Brettschneider tweeted that it is a “near lock” that Fairbanks will have its warmest December on record.

In a bit of irony, the forecast is for colder weather on Hawaii’s Big Island peaks, where one to two feet of snow is predicted, than in Anchorage over the next few days.

Alaska’s pervasive and persistent warmth is the result of a bulging ridge in the jet stream that has allowed mild air from the Pacific Ocean to flood the state. This is the same jet stream pattern bringing unusually warm, dry and fire-inducing weather to California and, on the flip side, cold to the eastern United States.

High altitude weather pattern forecast by European model shows massive upper level ridge over Alaska — the same pattern which has brought the state warm temperatures for much of this month. (
But the exceptionally warm weather in Alaska is not a mere reflection of the current weather pattern but part and parcel of the state’s long-term temperature trend. Alaska’s average temperature reached its highest point since records began in 1930.

Extremely mild this month in Alaska, but that's hardly new. The 60-month running average temperature (through November), which smooths out individual El Niño & La Niña years, is higher now than any time in the past 88 years. #akwx #Arctic
View image on Twitter
Extremely mild this month in Alaska, but that's hardly new. The 60-month running average temperature (through November), which smooths out individual El Niño & La Niña years, is higher now than any time in the past 88 years.  @Climatologist49
Alaska is responding to climate change, warming the Northern Hemisphere’s high-latitude regions more than anywhere. Just last week, NOAA’s latest report on the Arctic said that it “shows no sign of returning to reliably frozen region of recent past decades.”

In his blog post A new green land, Alaskan journalist Craig Medred lamented the great thaw occurring over his state. “For Alaskans who love real winters,” he wrote, “there are only two words for what it has brought to the start of winter … ‘This sucks.’ ”

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