OAKLAND -- Pacific Gas & Electric Co. on Thursday night started turning off the power in parts of the Bay Area as high winds and low humidity arrived in the region.

Power lines in Napa, Solano and Sonoma counties were being de-energized as of 7 p.m., according to the utility.

The counties of Alameda, Colusa, Contra Costa, Glenn, Lake, Mendocino, Santa Clara, Shasta, Tehama and Yolo were also expected to see a public safety power shutoff Thursday.

On Friday and Saturday, additional shutoffs will be required for the counties of Alameda, Butte, Colusa, Contra Costa, Fresno, Glenn, Lake, Madera, Mariposa, Mendocino, Merced, Monterey, Napa, Plumas, San Benito, Santa Barbara, Santa Clara, Santa Cruz, Shasta, Solano, Stanislaus, Tehama and Yolo, according to the utility.

The planned outages are intended to prevent wildfires as a weather system brings high winds and low humidity levels to the region.

The National Weather Service is predicting offshore winds of 25 to 35 mph with gusts up to 50 mph and daytime relative humidity as low as 10%. Much of the Bay Area and Central Coast will be under a red flag warning from 11 p.m. Thursday to 5 p.m. Saturday.

Temperatures are not expected to exceed the mid-80s, but as NWS meteorologist Matt Mehle noted, "You don't need to have the hot temperatures to have fire concerns."

"We've had fires in December," Mehle said in an interview Thursday. "We've had them in January. We've had them when the temperatures are in the 40s, 50s and 60s."