Another oscillation in the Pacific helps determine Northwest weather

The Puget Sound is a big part of life in Seattle. It's a connection to the outlying communities and a connection to the Pacific Ocean. And hundreds of miles out in the middle of wide open water, there's a whole lot of information that scientists have been

BOISE - The Puget Sound is a big part of life in Seattle. It's a connection to the outlying communities and a connection to the Pacific Ocean. And hundreds of miles out in the middle of wide open water, there's a whole lot of information that scientists have been gathering to help determine what to expect when it comes to rain in Seattle or even snow in Idaho.

Since the first weather satellite was launched in 1960 meteorologists have been able to see a lot of what was coming when it comes to weather.

"However, there's no substitute for getting in the water," says Ken Connell with Seattle's Pacific Marine Environmental Lab. He is talking about technology that is a bit less than space-age but has been in place in the Pacific since the 1980s.

"So, there's about 55 of these in the Pacific, 18 in the Atlantic, and about 30 in the Indian Ocean," says Connell, referring to the lab's tropical flex moorings, or T-flex buoys. They're used to gauge wind, temperatures, precipitation, and radiation. But it's the data they've pulled from the depths of the Pacific that has led to groundbreaking forecasting.

"That kind of revolutionized our look at the El Niño/La Niña phenomenon, being able to monitor that," says Nick Bond, Washington's State Meteorologist.

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He says the El Niño/La Niña phenomenon, the fluctuation of sea-surface temperatures along the equator, has been known about for hundreds of years. But since the '80s they've been able to predict its probability because of T-flex buoys.

It was about that time another phenomenon was surfacing known as the Pacific Decadal Oscillation. Identified in the late 1990s, it's illustrated by a boomerang of warmer-than-average sea temperatures along the western coast of North America.

"And that pattern kind of reverses every once in a while," says Bond. "And (it) kind of stays in that state for an extended period."

Whereas El Niño/La Niña is on an irregular two- to seven-year cycle, the DPO shows a pattern that covers, well, decades.

Data collected based on estimates before the 1980s show cooler-than-average temperatures from the 1950s into the 1970s. And from the late 1970s until the turn of this century, sea surface temperatures were warmer. Other than a few anomalies, weather conditions seemed to mirror those phases.

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Now, it appears, we are sliding into a negative, or cooler, phase.

So, how does that knowledge help forecast weather across the West?

"Well, we don't fully understand that," admits Bond. "But obviously, when the water is either warmer or colder than normal the atmosphere is responding to that in terms of how warm or cool it is."
There are still too many factors in play to say there is a direct correlation with decadal oscillation but with more knowledge comes more confidence.

"We're just looking for an edge, right?" asks Bond. "And that would be really useful if we could say, 'We can't guarantee this but it looks like the dice are loaded for a cool, wet winter.' That would be useful information."

And ultimately that's the goal, to be able to make a precise prediction.

Even with the continuing efforts to stack the deck, Bond says predicting the weather more than a year out with 100 percent certainty is a bit of a gamble. And, he says, Mother Nature doesn't always play fair, pointing to last winter as evidence of that.

But with the information continuing to be gathered out in the Pacific, forecasters hope to eliminate a few more of those wild cards.

"If we really knew what the ocean was doing and how it impacted weather patterns," Bond says. "Then that would help us a lot in making predictions, everything from out a season, a few years, maybe even a decade."

© 2017 KTVB-TV


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