Will a La Niña winter improve the drought in Northern California? It’s complicated

Everyone across California may experience La Niña weather conditions this winter. According to the National Weather Service last week, there is an 87% chance of La Niña starting December to February.

On average, La Niña will occur every three to five years, but this upcoming one will mark the second consecutive La Niña winter.

La Niña, and it’s counterpart, El Niño, are climate patterns in the Pacific Ocean that can have worldwide effects on weather, wildfires, ecosystems and economies.

During El Niño, winds are weaker and warm water moves towards the West Coast, whereas with La Niña, which means “little girl” in Spanish, trade winds are typically stronger.

“Off the west coast of the Americas, upwelling increases, bringing cold, nutrient-rich water to the surface,” the National Oceanic and Atmospheric Administration wrote on its website about La Niña. “These cold waters in the Pacific push the jet stream northward.”

The impacts to weather that La Niña will bring will vary from region to region, depending on its high-pressure system. Last year’s La Niña was a dry one.

“We’ve had a lot of wet La Niña years. It’s just that the probabilities tend to slightly favor it to be a little bit of a drier year,” said Craig Shoemaker, a meteorologist and climate program manager at the National Weather Service. “But that doesn’t necessarily mean this year is going to be a dry year.

And we’re starting off on the wet side.”

He said the high-pressure is further in the West, allowing the storm systems to affect the area. But this isn’t for certain yet.

“The beginning part of the La Niña looks that way, the pattern that we’re in right now is looking wetter,” Shoemaker said.

He added that while there is more potential for precipitation in late October to early November, the long-range forecast from the Climate Prediction Center indicates that there could be a dry period during the later phase of La Niña.

“That’s the problem with La Niña,” he said. “You can go from one extreme to the other very quickly.”

California, specifically Northern California, is experiencing its second year of a severe drought, according to the Mercury News. However, with La Niña, Northern California is likely to experience drought improvement, the NOAA reported.

“Consistent with typical La Niña conditions during winter months, we anticipate below-normal temperatures along portions of the northern tier of the U.S. while much of the South experiences above-normal temperatures,” said Jon Gottschalck, chief of the operational prediction branch at NOAA’s Climate Prediction Center, in the report.

However, NOAA’s forecast splits Northern California in half, Shoemaker said. This means north of Chico and Red Bluff will have a chance of a normal to slightly above normal water year. But Sacramento southward, drought can continue or worsen with La Niña.

“Their drought outlook runs along I-80, basically, so south of I-80, their forecast is drought persists,” he said. “North of I-80, drought persists but maybe some improvements.”

In terms of preparing for this winter, Shoemaker recommends bracing yourself for flooding because it can happen even during dry years.

You can start getting ready for this winter season and its upcoming storms by following tips here.

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