As strong, gusty winds arrive, the National Weather Service issued a Red Flag warning for parts of the Bay Area beginning at 11 p.m. Tuesday and extending through 3 p.m. on Wednesday.
Dry, off-shore winds are expected, prompting PG&E to announce Sunday that public-safety power shutoffs (PSPS) would likely be necessary for customers in 16 California counties, including around 2,000 customers in Napa and Sonoma counties. PG&E is now regularly in the practice of powering down its electrical lines during times of high fire danger and wind, and they say that PSPS events are a last resort.
As of Monday night, PG&E sent out one-day notifications of the shutoffs to 48,000 customers in total. The map below shows where the power is going to be shut off.
The weather service is saying that wind gusts could be between 45 and 55 miles per hour at higher elevations, and the Red Flag map includes wide swaths of the East Bay, as well as Sonoma, Napa, Solano, Yolo, and Sacramento counties.
The greatest area of fire threat, according to the weather service, are the northeast Napa Mountains. And the highest winds are expected Wednesday morning.
The South Bay hills east of San Jose, along with western Sonoma County and the Marin County hills are considered "low risk."
"The low-pressure system is trending north,” says NWS meteorologist Brooke Bingaman, speaking to the Mercury News. “The southern side of that trough is going to be moving along Northern California, and the air is going counter-clockwise. When it gets more east, we’ll be on the back side of the trough, and we’ll get those northerly winds. The red flag warning will be for that time when the back side of the trough is moving through.”
The low-pressure system is also having the added effect of cooling off the inland Bay Area, which saw some triple-digit temps on Monday. Temperatures are expected to top out today in the 80s.
Gusty winds have already been fueling fire growth in the Dixie and Caldor fires up north. The Caldor Fire, which broke out Saturday in El Dorado County and was 400 acres as of Monday morning, exploded overnight to 6,500 acres and is still 0% contained as of Tuesday morning.
The month-old Dixie Fire, which is the largest single fire in state history and the second-largest overall, has grown in recent days to over 604,500 acres, and is 31% contained.