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No need to go to the desert for the winter: It'll be dry here

Skiers may want to hold off on buying that new set of snow skis for the coming winter.

Umbrellas still will come in handy but there may not be enough rain to seriously challenge river levees.

El Niño is back and that usually means a mild Northwest winter with less rain and higher temperatures than normal, one of the National Weather Service’s top climatologists said Wednesday.

Ed O’Lenic, operations manager for the Climate Prediction Center near Washington, D.C., was the star of the annual Pacific Northwest Winter Weather Outlook. More than 100 emergency managers, flood fighters and public works officials attended the meeting at the National Oceanic and Atmospheric Administration’s Seattle headquarters along Lake Washington.

Seattle was chosen by the Weather Service for one of only four climate “road shows” being held across the country. The weakened Howard Hanson Dam on the Green River that could inundate 35 miles of South King County has drawn national attention.

Armed with charts and statistics and computer models, O’Lenic painted a picture of an El Niño winter that could give the area a respite from the stormy weather and floods of a Pineapple Express.

El Niño is a cyclical warming of the Pacific Ocean at the equator that can dramatically affect weather in North America. It moves the jet stream south toward California and reduces the chance of storms in the Northwest.

“We have a weak El Niño condition across the equatorial Pacific,” he said. “The (computer) models say it’s likely to strengthen and last through the winter.”

That strengthening could occur by early November, he said, and if it does, it would “move us away from a risk of heavy rain early.”

“If you have a weak El Niño it tends to be wet and I would be prepared for a little extra wetness here. … Things can flip from wet in the beginning of the winter to dry later in the winter,” O’Lenic said.

In 2006-07, a weak El Niño winter produced a record flood, a snowstorm and a windstorm.

Using data from El Niños dating back to 1950, he said they have found El Niños generally to be dry.

Dry also means less snow in the Northwest mountains, he said.

The prospect of less volatile weather was welcomed by Steve Bailey, head of emergency management for Pierce County, who attended the conference.

“We’re due,” he said.

Last winter, two flood-producing storms and a snow storm smacked Pierce County hard.

A drier winter also would be welcome news to South King County and the Green River cities of Auburn, Kent, Renton and Tukwila. The Howard Hanson Dam that controls flooding on the Green River is no longer able to hold back the Green River in the event of a major rainstorm.

Hillman Mitchell, emergency manager with the City of Tukwila, explained that erosion has occurred in the dirt abutment next to the dam. Until it is fixed, he said the U.S. Corps of Engineers, which operates the dam, will have to let the river flow through the dam.

The result would be a swollen Green River that could overtop levees or force levees to fail.

The result, Mitchell said, would be a lake in South King County 35 miles long, a mile wide and 3 to 12 feet deep. The Corps, the cities and King County are preparing for the worst, Mitchell said.

Asked if Puget Sound-area residents should feel relieved by the prospect of an El Niño winter, O’Lenic urged preparedness:

“I would say everyone should take it upon themselves to be prepared as they can and that means to get all the information about what’s going on and what’s likely to happen.”

Mike Archbold: 253-597-8692

mike.archbold@thenewstribune.com

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