dpBay Area residents woke up on Thursday morning to drizzle, a reminder that winter is around the corner.
The National Oceanic and Atmospheric Administration expects above-normal amounts of rain and snow across California this winter, according to a monthly outlook published on Thursday.
“The odds are increasing that it will be an above-normal winter as far as precipitation in California,” Jan Null, a meteorologist and private weather consultant with Golden Gate Weather Services, told SFGATE by phone Thursday. “But there’s no guarantee … Right now, it’s like we have a six-sided die, and five of those sides say above-normal and one side says near-normal or below-normal.”
NOAA’s Climate Prediction Center generally expects Southern California’s rainy season to start first and to have the greatest chances of more precipitation than normal. Beginning in December, however, elevated chances of above-normal rainfall wash over all of California. Statewide, January, February and March have the highest odds of heavier precipitation. Temperatures will likely trend warm only for Northern California through at least February, potentially impacting the snowpack.
“The evolving El Nino is the primary driver of the outlook,” Jon Gottschalck, chief of operational prediction for NOAA’s Climate Prediction Center, said in an email to SFGATE Thursday.
El Niño is the warm phase of a natural pattern that emerges in the central and eastern tropical Pacific. Temperatures in the Pacific Ocean are still rising as this year’s El Niño continues to rapidly strengthen. The spike in the Pacific’s heat during El Niño years can drive winter weather in California and across the globe. Generally, El Niño causes the jet stream over the Pacific to shift southward, raising the odds of a wetter season in Southern California.
The new NOAA outlook aligns with those expectations. The latest seasonal forecast from the European Centre for Medium-Range Weather Forecasts also shows extremely high confidence for a wet winter in California.
“It’s always good when we see multiple models going in the same direction,” Null said. “This solidifies that the odds are leaning toward a wetter-than-normal year, but we don’t know how much wetter. And we don’t know how that rain will be distributed through the year.”
Meanwhile, after a few tiny droplets fell across the Bay Area into Thursday morning — mostly concentrated in the East Bay hills — due to a superthick marine layer, the weather should warm up and dry out, National Weather Service meteorologist Dylan Flynn told SFGATE by phone Thursday.
