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La Nina on the horizon? California's wild weather year could get even weirder

Hayley Smith, Los Angeles Times on

Published in Weather News

LOS ANGELES — Storm-soaked California is still in the clutches of a wet El Niño winter, but in an unexpected plot twist, La Niña could be hot on its heels.

The El Niño-La Niña Southern Oscillation, or ENSO, is a climate pattern in the tropical Pacific that can influence weather worldwide and across the Golden State, although its outcomes are never guaranteed.

Typically, El Niño is associated with warm, wet winters in Southern California, while La Niña is associated with cooler and drier conditions.

So far this year, El Niño has delivered on that promise. The pattern intensified in recent months, becoming what is now believed to be the fifth-strongest El Niño on record, according to an advisory the National Oceanic and Atmospheric Administration issued Feb. 8.

Since December, California has been pummeled by intense atmospheric rivers, including three storms that dropped record-breaking rainfall in Oxnard, San Diego and Los Angeles. The latest storm killed at least nine people and triggered landslides, debris flows and two tornadoes.

But California’s wild weather ride may not be over yet, as there is now a 55% chance La Niña could develop sometime between June and August, the advisory says. There is a 77% chance it could develop between September and November.

 

“We look at a lot of very state-of-the-art climate models, and there’s a lot of consensus among these models that we will potentially transition into a La Niña,” said Michelle L’Heureux, a climate scientist with NOAA’s Climate Prediction Center. “Taken all together, that’s why we issued the watch.”

La Niña tends to favor the opposite pattern of El Niño, L’Heureux said. During La Niña, the central and eastern Pacific Ocean cools, and the jet stream — the river of air that moves storms eastward across the globe — shifts toward the north. The effect essentially creates a big ridge in the north Pacific Ocean, which “can help dry things out across the southern tier of the United States, and that is inclusive of California,” she said.

L’Heureux cautioned that it is still very early in the year to make any predictions about how next winter could play out in California. ENSO is more like a “great nudger” that encourages weather systems to reoccur along a certain preferred pathway, as opposed to a guaranteed outcome.

“It’s still not a slam dunk,” she said of La Niña. “There’s still a 1 in 4 chance that this won’t happen, and seeing that progress will be important for saying something about the impacts. Because once it emerges, we can then be slightly more confident in certain impacts.”

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