Meteorologist predicts variation on El Nino pattern: A wet PNW winter

An Eastern Washington University meteorologist says he has a different take on what El Nino will do this winter in the Northwest.

By MITCH LIES For the Capital Press 

Eastern Washington University meteorologist Robert Quinn said he believes that contrary to most El Nino weather patterns, the Pacific Northwest will see excessive rain this winter.

Speaking at the 75th annual convention of the Oregon Seed Growers League in Salem in December, Quinn noted that an El Nino weather system typically will split into two storm tracks: a southern half, which brings warm, wet conditions to California; and a northern track, which brings with it drought-like conditions to the Pacific Northwest.

Quinn said the southern half will stay true to form and produce “a good, strong flow of warm, wet Pacific storms coming in off the ocean, which is good news for drought-ridden California.”

The northern half, however, will see a deviation from the norm, he said.

“The end result normally in the Pacific Northwest is we end up under a ridge of high pressure and end up with a winter drought. But there is ‘Variation B.’ Sometimes the southern branch of the storm track is so powerful that we (in the Pacific Northwest) get clipped by the northern part of the southern branch. So the end result is … we end up with a warm, wet winter.

“My prediction is we’re going to see the northern part of that California-storm track sweep into Oregon and parts of Washington,” Quinn said, “and we’re actually going to end up with a warm, wet winter.”

The strongest El Nino in modern history was in 1982-83, Quinn said. “It turns out that ’82-’83 was a warm, wet winter in the whole West,” he said. “And this El Nino is as strong probably as the ‘82-’83 El Nino.”

Quinn said El Nino starts as “a warming of the Eastern Equatorial Pacific off the coast of Southern Ecuador and Northern Peru” that occurs every five to seven years.

In concert with the warming, trade winds weaken and, as such, do not drive a typical level of cold water toward the Western Pacific. “So water piles up in the Western Pacific … and it is like a dam,” he said.

“It takes about two months to get to the Peruvian Coast,” Quinn said. “The end result is quite a weather change.”

Quinn said he expects El Nino to fizzle by summer, given that the high sea surface temperatures created in the summer and fall by El Nino typically are destroyed by its winter pattern.

“I think you are still going to see the normal hot, dry summer,” Quinn said.