SAN FRANCISCO– A large “diablo wind” – infamous in the fall for its hot, dry gusts – is expected to blow across Northern California on Thursday evening, lowering humidity and increasing the risk of wildfires.

Forecasters have issued red flag warnings of fire danger through Saturday from the Central Coast through the San Francisco Bay Area and into northern Shasta County, not far from the Oregon border.

According to the National Weather Service, sustained winds of 35 mph are expected in many areas, with possible gusts of up to 64 mph along mountain peaks.

“This could be the most significant wind event of the year so far,” said meteorologist Brayden Murdock of the agency’s Bay Area office. “We want to warn people to be careful.”

During a diablo wind, common in the fall, the air is so dry that the relative humidity drops, causing vegetation to dry out and be ready to burn. The name – “diablo” is Spanish for “devil” – is informally applied to a hot wind that blows from inland toward the coast near the San Francisco region as high pressure builds over the west.

Pacific Gas and Electric Co. said it was prepared to turn off power to a small number of customers in areas where strong wind gusts could damage electrical equipment and cause fires.

Targeted power shutoffs were also possible in Southern California, where another infamous weather phenomenon, the Santa Ana winds, is expected Friday and Saturday.

Winds around greater Los Angeles won’t be as strong as in the north, with gusts between 25 and 40 mph (40 and 64 kph) possible in the mountains and foothills, said Mike Wofford, a meteorologist with the state’s office weather service in los angeles.

“I think it will be more moderate,” he said Wednesday. “But the risk of fire is still present.”