Weather

Expect warmer conditions for the start of Alaska's winter

Arctic sea ice is scarce, ocean waters are warm and the coming months are expected to be warmer than normal in most of Alaska, weather experts say.

The National Weather Service's  Climate Prediction Center forecasts that most parts of Alaska next month are likely to be significantly warmer than the 1981-2010 average, thanks to more ocean heat and less sea ice.

For November through January, most of the state is expected to be warmer than normal, with that trend concentrated along the coasts. Interior sections of Alaska have an equal chance to be in the normal, high or low range for temperatures, according to the center's newly released outlook.

Sea-surface temperatures near Alaska have continued to be above average as they have for the past three years, said Rick Thoman, the National Weather Service's climate science and services manager in Alaska.

"It's warm, warm, warm," Thoman said in a monthly climate forecast briefing held Friday.

There has been a marked warming trend in the North Pacific — "otherwise known as the Blob," he said of the mass of warm water that developed in 2013 and has persisted in various forms since then.

Farther north, sea ice is scarce compared to normal, with extent in both the Chukchi and Beaufort seas at the second-lowest October levels in the satellite record and with the Arctic-wide extent 20 percent lower for this time of year than it was last year, Thoman said.

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There is "quite a dramatic lack of sea ice for this time of year," he said.

Sea-ice extent is defined as the area where ice covers at least 15 percent of the water's surface.

Arctic-wide, sea ice reached its second-lowest annual minimum in the satellite record going back to 1979, according to the National Snow and Ice Data Center in Boulder, Colorado. As of Thursday, sea-ice extent was as low as it has ever been for that date in the satellite record, according to the National Snow and Ice Data Center.

Low sea ice is expected to have long-lasting effects on North Slope weather. For all the months in the coming year, temperatures on the North Slope are likely to be significantly above the 1981-2010 average, according to the latest Climate Prediction Center forecasts. Behind those North Slope temperature anomalies, "changes in the sea ice are the overriding driver," Thoman said.

Still, fans of normal, snowy Alaska winters can take heart, and not only because Anchorage received the winter's first snowfall on Friday.

Chances are that this winter will bring a weak version of the weather phenomenon called La Nina, an oceanic pattern of cooling that is the flip side of the Alaska-warming El Nino, the forecasts say.

The National Weather Service has resurrected its La Nina forecast after dropping it earlier in the year. There is a 70 percent chance of a La Nina developing early in the winter and a 55 percent chance of it lingering through the season, according to the latest forecast.

"There's not a lot of correlation between when the first snows come and what the overall total is. But given that we are in a La Nina and not in El Nino, there's reason for hope," he said. "Keep your fingers crossed."

In Fairbanks, however, the late arrival of snow this winter might be a signal of conditions to come in the next months.

Fairbanks did not have measurable snow cover on the ground until Thursday, according to the Fairbanks regional office of the National Weather Service. Records to date show no above-normal winter snow accumulations in Fairbanks in any of the years when the first snow cover came later than Oct. 15, Thoman said.

Yereth Rosen

Yereth Rosen was a reporter for Alaska Dispatch News.

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