Environment & Science

Does the new La Niña forecast mean a dry winter for California?

Sea surface temperature in July 2016 compared to the 1981-2010 average. Cooler-than-average waters are present in the central tropical Pacific. NOAA Climate.gov map, based on GEO-Polar data.
Sea surface temperature in July 2016 compared to the 1981-2010 average. Cooler-than-average waters are present in the central tropical Pacific. NOAA Climate.gov map, based on GEO-Polar data.
Courtesy of NOAA's Climate.gov

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According to a new forecast from the National Weather Service's Climate Prediction Center, it's likely that the La Niña weather pattern will show up this winter.

The likelihood that it will show up this winter is the same as last month: a 55 to 60 percent probability. That's a downgrade from June, when it was 75 percent.

While El Niño is associated with warmer waters in the equatorial Pacific and warm, wet winters in Southern California, La Niña can be tied to cooling waters, and is better known for keeping things drier in the southern part of the state. 

But if the past year has proven anything, it's that nothing's for certain. The powerful El Niño was supposed to drench all of California. In the end, Northern California's drought was eased slightly, but southern California was left dry

There is a presumption "that if we have La Niña that somehow that’s going to make the drought worse and it’s not entirely obvious that that’s actually the case," said Stanford climate scientist Daniel Swain. 

Swain explained that it appears that La Niña could be fairly weak, opening up the possibility for normal rainfall in Southern California. But then again, the past few winters the region's rainfall has been lower than average even without La Niña around. 

The National Weather Service's Climate Prediction Center will update its La Niña forecast next month.