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Experts predict that California will see an extremely rare La Niña event

Experts predict that California will see an extremely rare La Niña event

The National Oceanic and Atmospheric Administration states in its USA winter weather forecast that La Niña will occur from December to February for the third consecutive year.

It is not unusual to see two consecutive La Niña winters, but what American forecasters call “triple sauce” is unusual. If we go back some 70 years, this has happened only twice.

“It’s happened in the past, but it’s not normal,” said Brian Garcia, a meteorologist with the National Weather Service.

What does this mean for the water-hungry San Francisco Bay Area? Last winter was abnormally dry in the middle of a La Niña pattern. Could the region see the same this winter?

With La Niña continuing, NOAA’s winter forecast favors wetter weather in the Pacific Northwest and drier conditions in southern California for December 2022 through February 2023. Northern California and the Bay Area fall in the middle, where chances of winter in one direction or another they are not strong. The outlook map suggests that a warmer winter is slightly more likely than a colder one in the Bay Area, while above-average, below-average, and normal precipitation are equally likely.

The rain forecast is a result of data from past La Niña winters. Although the Bay Area has had several abnormally dry winters during La Niña years, it has had both average and unusually wet years.

“An equal chance forecast in your area actually means that the current climate signals and the reliability of historical forecasts in your region do not allow for a safe or reliable forecast shift in climatological probabilities,” Jon Gottschalk, head of NOAA’s Center for Climate Prediction Forecast Branch, wrote in an email. . “So right now the odds for your area are 33% for each category. Unfortunately, there is no clear shift in either direction. Your area is known for high variability or outcomes during winter La Nina events and therefore equal odds are predicted.”

NOAA has released its 2022-23 winter weather forecast.

NOAA has released its 2022-23 winter weather forecast.

NOAA

La Niña is a weather phenomenon that occurs when equatorial waters in the eastern and central Pacific Ocean cool to below normal averages. The better known El Niño, the reverse of La Niña, is when the waters warm up. Both can affect atmospheric conditions around the world, including the jet stream and the storm stream.

El Niño and La Niña are climate oscillations, natural changes in sea temperature, air pressure and wind direction that affect weather around the world, according to NOAA. While El Niño and La Niña can affect winter weather, many other oscillations are also in the mix, including the Arctic and Madden-Julian Oscillations.

“El Niño and La Niña, they’re the superstars of the team,” said local forecaster Jan Null of the Golden Gate Weather Services SFGATE said by phone. “They’re the most likely to have a big night. Some of these other players off the bench can come in and still impact the game.”



The big twist in this year’s forecast is that NOAA is predicting that La Niña will transition to what is called ENSO neutral as early as February. In ENSO neutral, equatorial waters are at average temperatures. A similar pattern occurred in 2016-17, when the winter started dry but ended wet.

“We had one or two storms in 2016, and then when we got into the new year and came out of La Niña, the storm opened up completely,” said Garcia, who works for the Bay Area Weather Service office. “We had two months of non-stop rain. It felt like non-stop rain. We had so many stormwater rivers coming through our area. That was the year Coyote Creek flooded in San Jose.”

Garcia predicts that in 2022-23. could have proceeded similarly.

“It’s going to rain this winter,” he said. “The question is, ‘How much rain are we going to get?’ From the things I’ve seen, it looks like it’s going to be loaded. We’re going to have a couple of fronts come through and give us some rain during the latter part of this calendar year, but I really think next calendar year is going to be when we get hit; probably from the end of February to April to be our window this year. If we get something in March, we have the ‘Miracle March.’ If we get something in April, we have our ‘Amazing April.'”

Null is not prepared to make a prediction and sticks to the NOAA forecast that does not favor one scenario over another.

“I don’t think we just know,” he said. “If anyone really had the answer, they’d be the richest person on the planet.”

This news has been updated.



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