It’s only mid-December and already California’s weather is putting the state on high alert for winter — and it’s likely far from over.
Just this past week, a major wildfire raced into Malibu, fueled by dangerous Santa Ana winds, and a powerful storm dumped feet of snow in the mountains, caused flooding in the Bay Area and in Santa Cruz County, formed a tornado.
And now, forecasters warn that similar conditions are likely to return this week, with high winds in Southern California prompting further fire concerns, and a series of atmospheric rivers bound for Northern California that could bring more flooding and headaches for travelers.
These diverging winter weather patterns are providing the latest reminder about how much California can differ climatologically, especially when it comes to early-winter precipitation.
“It’s fairly common to have other parts of the West get targeted and we kind of get left out,” Robbie Munroe, a National Weather Service meteorologist in Oxnard, said of Southern California’s relative dryness to up north. He said the sharp contrast often eases by January or February, when the jet stream — which tends to direct moisture-laden storms — shifts further south.
So even as Northern California this weekend dealt with significant rainfall and high winds — closing roads in Sonoma County, downing trees along the North Bay Coast, cutting off power to thousands — firefighters in Southern California continued to work on the bone-dry landscape around the Franklin fire in Malibu, which was just over 50% contained early Monday.
The Southland remains in high fire season, which could last into the New Year without a wetting rainfall, and forecasters say more Santa Ana winds are on the way.
Beginning Tuesday afternoon, much of Ventura County and western Los Angeles County will be under a red flag warning, with northeast winds reaching up to from 40 mph and some isolated gusts hitting 60 mph, especially in the San Gabriel, Santa Susana, and Santa Monica Mountains.
Munroe said the winds are not expected to be as strong or dry as the winds that helped fan the Franklin fire last week, but conditions are still delicate with low humidity and dry brush. This “traditional Santa Ana corridor,” which includes the region that saw the Mountain fire explode in November, will again have the potential to see extreme behavior if a fire sparks, Munroe said.
“There is still plenty of shared concern by meteorologists and fire personnel across the area due to the receptive fuels that we have seen recently,” the fire weather warning said early Monday, which was later updated to a red flag warning.
There was some early hope that Southern California could get significant rain by the end of the week, when a string of wet storms are expected to make their way south from the Gulf of Alaska, but those have mostly evaporated.
“The greatest amount of rain impacts will stay to our north, more than likely,” Munroe said.
This next period of wet weather is forecast to kick off in Northern California Friday, bringing more rain, snow and potential flooding to the region as a “series of atmospheric rivers push inland,” according to the weather service’s Weather Prediction Center.
“We’re anticipating a wet week next week,” said Crystal Oudit, a National Weather Service meteorologist in Monterey. “We might stay in a wet pattern for… Christmas week.”
That precipitation will come days after much of Northern California was soaked this past weekend and into Monday. The most significant storm brought drenching rains and high winds Saturday, prompting the first-ever tornado warning in San Francisco, where wind gusts up to 80 mph caused widespread damage.
While a twister didn’t end up touching down in San Francisco, one did just south in Scotts Valley in Santa Cruz County.
The tornado recorded wind speeds up to 90 mph as it tore a path almost 30 yards wide for nearly a third of a mile, according to the National Weather Service. At least three people were injured as the tornado downed trees and power poles, ripped off branches, overturned vehicles and damaged street signs, the weather service reported. It was classified as a weak E-F1, which the National Weather Service considers a moderate tornado on its scale from EF-0 to EF-5.
While tornadoes aren’t regular occurrences in the Bay Area, there have been several recorded in the area, including seven others in Santa Cruz County, the National Weather Service reported.
The storm over the weekend also dumped significant snow across the northern Sierra Nevada, including more than two feet of fresh powder in Lake Tahoe. Quick bouts of rain temporarily flooded some roadways and underpasses in the Bay Area, submerging cars in one low-lying street in Livermore.
It doesn’t appear the next round of storms beginning Friday have any notable winds associated with them, Oudit said, but she noted that some forecasts are still too far out to know for sure.
Times staff writers Andrea Chang and Ben Poston contributed to this report.