Will the Bay Area have a wet winter?  Local forecasters intervene.

Will the Bay Area have a wet winter? Local forecasters intervene.

The National Ocean and Atmospheric Administration said in its U.S. winter weather forecast that La Niña will make an appearance from December through February for the third year in a row.

It’s not uncommon to see two consecutive La Niña winters, but what US forecasters call a “triple dip” is rare. Going back about 70 years, this has only happened two other times.

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

What does this mean for the water-starved 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 the persistence of La Niña, the NOAA winter forecast favors wetter weather in the Pacific Northwest and drier conditions in Southern California from December 2022 to February 2023. Northern California and the Bay Area are in an intermediate zone, where the chances of winter going one way or the other are not solid. The outlook map suggests that the chance of a warmer winter is slightly higher than a colder winter in the Bay Area, while there are equal chances of above-average, below-average precipitation. average and normal.

The rain forecast is the result of data from past La Niña winters. While the Bay Area has experienced more abnormally dry winters during La Niña years, it also has average years and exceptionally wet years.

“Equal opportunity forecasting in your region actually means that current climate signals and the reliability of historical forecasts in your region do not allow for a safe or reliable forecast change in climate probabilities,” said Jon Gottschalk, chief from the NOAA Climate Prediction Center. forecast branch, wrote in an email. “So the odds right now for your region are 33% for each category. No clear change either way unfortunately. Your region is known for high variability or results during La Nina winters and c That’s why equal chances are provided.”

NOAA has released its weather forecast for the winter of 2022-23.

NOAA has released its weather forecast for the winter of 2022-23.

NOAA

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

Null said that while La Niña influences winter weather, many other factors are at play, including a handful of oscillations, such as the Arctic and Magellanic-Julian oscillations.

“El Niño and La Niña are the superstars of the team,” Null said. “They have the greatest likelihood of having a big night. Some of those other bench players can come in and still influence the game.”

A big twist in this year’s forecast is that NOAA is predicting that La Niña will shift to what’s called neutral ENSO as soon as February. In ENSO, the equatorial waters are at average temperatures.

A similar trend occurred in 2016-2017, when winter started dry but ended with rain.

“We had one or two storms in 2016, then once we got through the new year and got out of La Niña, the storm opened up completely,” said Garcia, who works for the service’s office. Bay Area weather report. “We had two months of non-stop rain. It felt like non-stop rain. We had so many atmospheric rivers flowing through our area. This was the year Coyote Creek flooded in San Jose.”

Garcia predicts 2022-23 could play out the same way.

“This winter we will have rain,” he said. “The question is, ‘How much rain will we get?’ From the things I’ve looked at, it looks like it’s going to be delayed. We will have a few fronts passing and we will give some rain in the latter part of this calendar year, but I really think the next calendar year will be when we will be affected; probably late February to April will be our window this year. If we get something in March, we will have “Miracle March”. If we get something in April, we have our “Amazing April”. “

Null is not ready to make a prediction and sticks to NOAA forecasts which do not favor one scenario over another.

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

This news has been updated.

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