Tuesday, October 7, 2008

Winter’s on the way — Forecasters predict return to normal conditions

By Ben Histand
For the Redoubt Reporter

As temperatures drop, the approach of winter is becoming harder to ignore. In Cooper Landing, snow is descending to ever-lower altitudes, and as quickly as the mountains are turning white, the lowlands are losing the bright colors whose arrival marked the end of summer. Several night frosts have prompted more than a few residents to harvest potatoes from the garden, and fall pumpkins have made their debut at local grocery stores. Winter may not have arrived yet, but it is certainly on its way.

What kind of winter is in store for the Kenai Peninsula? After an anomalous summer that by National Weather Service statistics ranked as one of the coldest on record, residents may be wondering if the out-of-the-ordinary weather will continue. While speculations vary, on the whole, climatological data suggests that abnormal weather will not continue.

Dan Peterson, observation program leader with the National Weather Service’s Anchorage Weather Forecast Office, said that based on 30 years of climate records, his office estimates temperatures for the next three months will be near normal. According to the Western Regional Climate Center’s Web site, that would indicate fall temperatures averaging 34.6 degrees Fahrenheit in Kenai, and winter temperatures averaging 14.9 degrees.
With summer temperatures often struggling to top 60 degrees, however, a typical fall and winter may feel uncomfortably cold to some. Morgan Renney, of Soldotna, isn’t worried.

“I’m hoping for lots of snow,” he said. He said he’s looking forward to snowboarding Redoubt Hill in Soldotna and Mount Alyeska in Girdwood. Normal cumulative snowfall for Southcentral Alaska is 69.5 inches, and the first measurable snowfall typically comes in October. The record for latest measurable snowfall is Nov. 11, according to the National Weather Service Web site.

One possible factor influencing the cold summer temperatures was the La Niña effect, which refers to cooler-than-normal ocean temperatures in the eastern South Pacific that influence weather patterns as far away as Alaska. La Niña dissipated as summer passed, according to the NOAA, but ocean temperatures may still be influencing Alaska’s climate in other ways.

Martha Shulski, a climatologist with the Alaska Climate Research Center in Fairbanks, said temperatures in Alaska are significantly affected by a phenomenon known as the Pacific Decadal Oscillation, which, like La Niña, involves trends in ocean temperatures, but takes place over a much longer period of time. The Pacific Decadal Oscillation refers to cycling phases of warmer and cooler surface temperatures in the North Pacific, and these lead to warmer and cooler air temperatures in Alaska.

Historically, the PDO appears to shift every 20 to 30 years. The most recent observed shift, from a colder phase to a warmer one, was in 1976. Shulski said there is speculation, but no consensus, that the PDO is now shifting or has already shifted back to a colder phase. If it does shift, climatologists would expect mean temperatures in Alaska to drop on the order of a degree or two.

Dwain Gibson, a resident of the Kenai Peninsula since 1957, said he thinks accurate forecasts are difficult to come by.

“We’ve had a wet summer,” he said.

From what he can remember, wet summers are often followed by a severe winter. But he was reluctant to make a prediction about this year.

“You’ve got to just take it a day at a time,” he said.

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