October 17, 2008 in City

Winter forecast confounds experts

By The Spokesman-Review
 

The National Weather Service on Thursday issued a new weather outlook for December through February showing the Inland Northwest with equal chances of a mild to severe winter.

In addition, a climate expert at Eastern Washington University is also predicting a normal winter – about 45 inches of snow in the valleys – with good mountain snowpacks. Last year’s snowfall in Spokane was 92.6 inches.

Their outlooks are based in part on the fact that the water temperatures in the equatorial Pacific are normal this fall and that neither an El Niño nor La Niña – conditions known to affect winter weather across the U.S. – are occurring.

Last winter’s La Niña – a cooling of Pacific water along the equator – contributed to near-record snowfall in the Spokane region and below-normal temperatures. The warm cousin El Niño has in the past been associated with mild and often drier winters.

Forecasters at the Climate Prediction Center are giving “equal chances” of a mild, severe or normal winter.

“It’s another way of saying ‘flip a coin,’ ” said Ron Miller, science operations officer for the Weather Service in Spokane.

“One of the big signals is they are not looking at an El Niño or La Niña. They are looking at neutral conditions,” he said of the climate prediction scientists.

However, he said they are even less certain about the Pacific Northwest because of competing climate signals this fall.

“They actually did say the Pacific Northwest is giving them more trouble in their forecast than other parts of the country,” Miller told a workshop Thursday.

Professor Bob Quinn at Eastern Washington University, an expert in the connection between Pacific water temperatures and winter weather, said in a separate interview Thursday that he is expecting a winter that is closer to normal with rain and some snow into December. He said he expects a short spell or two of arctic cold around the end of the year and more persistent snow coming in late December, January and February.

“I see initially a fairly wet fall with some early snow in the mountains,” Quinn said.

“My suspicion is that we will eventually have a normal winter in terms of snowfall, which means we will get our 45 inches of snow,” he said, adding that snowfall in the mountains should be normal.

Last year in October, the Climate Prediction Center correctly foresaw the chance of higher precipitation in the Pacific Northwest, but missed the outlook for temperatures, which ended up being below normal for January and February, Miller said.

Scientists have learned over the years that ocean temperatures in the Pacific can have different effects on weather patterns. Quinn said warmer-than-normal water in the North Pacific should become a focusing mechanism for early-season rain and mountain snow.

Meteorologists in Spokane said that a neutral outlook for winter in the Inland Northwest can also be accompanied by harsh winters, according to climate records.


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