Thursday January 18, 2024
San Francisco Chronicle —
Statewide rain is expected across California this weekend, and El Niño’s fingerprints are all over the upcoming weather pattern.
Despite El Niño winters often favoring Central and Southern California for above-normal precipitation, the wet season has generally been off to a slow start across the state.
That will begin to shift in a more meaningful way Friday, when the subtropical branch of the jet stream, a distinct feature of El Niño, is expected to transport moisture toward the Golden State. Los Angeles and San Diego are forecast to receive 1 to 2 inches of rain, and San Francisco could measure 3 or more inches through Tuesday.
In California, how El Niño takes shape all comes down to the position of the jet stream, a ribbon of fast-moving air high in the atmosphere that guides storms across the Pacific Ocean.
Jan Null, a meteorologist with Golden Gate Weather Services and adjunct professor at San Jose State University, says the jet stream is “driven by temperature differentials.”