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El Niño is still a mystery

It’s unknown as to how weather phenomenon could help alleviate California’s drought

Posted: July 21, 2014 2:00 a.m.
Updated: July 21, 2014 2:00 a.m.
 

Like its name, El Niño is still an infant when it comes to what meteorologists actually know about the finicky weather phenomenon and how it impacts California’s rainy season.

“El Niño can happen any year. Sometimes you’ll have two or three years in a row when you have an El Niño going on,” said Logan Johnson, a National Weather Service meteorologist, who has studied the phenomenon and is tracking this year’s El Niño event in the Pacific Ocean.

“Or you may have a period of three or four years when you don’t have an El Niño happening. We don’t really know why it will repeat for several years in a row, but we do know that can happen sometimes.”

Any hopes of a strong El Niño bringing respite from the state’s three-year-old drought this winter fizzled with the release this month of data indicating a weak to moderate El Niño.

Scant data

While meteorologist know enough about El Niño to say reliably that strong events usually mean more rain for Southern California, the impacts of weak to moderate readings are unknown.

Serious research into what meteorologist call the El Niño Southern Oscillation began about 1950 — “just under 65 years of data,” Johnson said, leaving much still to be learned.

“Actually we wish there was better capability for seasonal forecasting, but the scientific capability for that is not very high,” said Jeanine Jones, interstate resources manager and state deputy drought manager at the California Department of Water Resources.

“This year the forecast is for an El Niño in the weak-to-moderate category, and those don’t provide a strong ‘signal’ for precipitation for Southern California.”

El Niño emits that “signal” only under certain circumstances and in certain locations, Jones said.

While a strong El Niño tends to soak Southern Californians, for residents in the central part of the state “it’s a mixed bag; it could go one way or the other.”

“El Niño is by no means the be-all and end-all of seasonal forecasting,” said Jones.

Rising temperatures

For a strong El Niño to be “born,” two key things need to happen. Temperatures in the southern Pacific Ocean need to rise two degrees or higher; and sea surface warming and the atmosphere must come together in what science calls a “coupling.”

“Basically, you have two components,” said Johnson. “One is the ocean temperature being warmer than normal. The other is the atmosphere beginning to react. When you have both of those going on, it’s coupled.”

Warmer air rising from the Pacific Ocean into the atmosphere triggers an increase in thunderstorms, completing the coupling.

“When you have thunderstorms going on in the Pacific Ocean, that actually puts heat into the upper level of the atmosphere,” Johnson said, “and what that does is it changes the jet stream’s position over the Pacific.

“When that happens, you really see the impacts on the West Coast’s weather.”

At the moment, meteorologists have yet to detect an oceanic-atmospheric coupling with this year’s El Niño, said Johnson.

“We don’t yet have a coupled event going on. We don’t yet see the effects on the atmosphere,” he said. “That’s another reason why it’s hard to say that this particular El Niño would result in a lot of rain for California.”

At the department responsible for managing and protecting the state’s water, Jones joked about the El Niño hype that surged immediately after the National Oceanic and Atmospheric Administration announced a few months ago that an El Niño was likely beginning this fall.

Many misconceptions

“Someone took that and ran with it and it sort of exploded after that,” said Jones. “That’s why the Weather Service began making a point of cautioning people” against snap calls.

Still ahead are three difficult months, said Johnson, when “we could start seeing the worst effects of the drought, since it’s been so dry.”

“We don’t want people to think that, ‘Well, El Niño’s coming so we won’t have to worry about” conserving water, he said. “That’s certainly not the case. We need to base our decision on what’s going on right now, and it’s been extremely dry.”

Jones isn’t surprised the phenomenon tends to stir up misconceptions, along with the weather.

“Keep in mind that El Niño originally got its name because its impacts were felt strongly off the coast of Peru, where it resulted in stronger catches for the fisherman there,” said the drought expert.

“They called it ‘El Niño’ because the phenomenon showed up around Christmas time — a reference to the Christ child.”

For now it’s probably best to take Jones’ advice: “Prepare for the worst, hope for the best.”

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