What does a weak La Niña mean for Southern California?

146271 full
146271 full

Right now, the globe is in the grips of a La Niña, a weather phenomenon that occurs when a patch of the Pacific Ocean near the equator cools down below average.

Typically, La Niña means plenty of rain for the Pacific Northwest and a warm, dry winter for Southern California. That's the pattern the National Oceanic and Atmospheric Administration, or NOAA, is predicting for this winter.

The 2016 winter precipitation prediction from the National Oceanic and Atmospheric Administration.
The 2016 winter precipitation prediction from the National Oceanic and Atmospheric Administration. NOAA

However, this year's La Niña is very weak compared to previous ones, said Bill Patzert, a climate scientist with NASA's Jet Propulsion Laboratory.

"This La Niña is puny, it’s almost a La Nada," he quipped.

That means its effects likely won't be as strong, he suggested, leaving open the possibility that places like Southern California may still get some large rainstorms this winter.

A strong La Niña from the winter of 1997-1998 (left), compared to this year's much less powerful La Niña (right). Photo: NASA / JPL.
A strong La Niña from the winter of 1997-1998 (left), compared to this year's much less powerful La Niña (right). Photo: NASA / JPL. NASA / JPL

Patzert thinks the region could even see the return of the atmospheric river known as a "Pineapple Express," a storm that usually dumps massive amounts of rain.

"When you are making out your Christmas list, I wouldn't put umbrella's at the top of your list, but I would definitely leave it on the list," he said.

So far, the Los Angeles area is already doing better this year when it comes to rainfall. Since October the city has seen about 1.40 inches of precipitation. This time last year, the total was just 0.46 inches, said Patzert.

Keep in mind though, trying to predict a California winter is like trying to guess the winner of the World Series in March.

Last year many forecasters, Patzert included, predicted monster rains due to a strong El Niño pattern. Those storms never materialized in Southern California.

Nate Mantua with NOAA thinks despite the weak signal, La Niña's effects will still hold sway over winter weather patterns.

"This includes increased odds for below normal rain and above normal temperatures in Southern California and the rest of the Southern US," he explained.

La Niña isn't the only pattern influencing weather in California, noted Daniel Swain, a climate scientist at UCLA.

"Models that take into account the overall state of the global oceans and sea ice conditions continue to suggest a drier than average winter for much of California, especially in the south ," he said.

Even if the region sees a few strong storms, total rain accumulation could still be below average too. So, one way or another, water will likely be tight in Southern California going forward.

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