SANTA CRUZ — It might be lights out for the weekend in many greater Bay Area homes by twilight Saturday, embattled PG&E announced Friday afternoon.

In a 2 p.m. announcement, the company expanded earlier outage estimates, saying that 850,000 customers in 36 counties across Northern California will lose power starting at 6 p.m. because of the winds it called “historic.” The shutdowns will continue through 10 p.m.

Approximately 44,945 in Santa Cruz County; 57,630 customers in Alameda County; 48,824 in Contra Costa County; 86,813 in Marin County; and 64,932 in San Mateo County will be without electricity. Santa Clara County is not affected, PG&E said.

Capitola officials said they anticipated, at a minimum, that those locations that were affected by the Oct.10 outages would be affected by this weekend’s event. In its Friday update, PG&E listed the affected Santa Cruz County communities of Aptos, Ben Lomond, Brookdale, Capitola, Corralitos, Felton, Freedom, La Selva Beach, Mount Hermon, Santa Cruz, Scotts Valley and Soquel. Officials said the best predictor to determine impact locations, however, is PG&E’s database for street-by-street planned outages at psps.ss.pge.com.

PG&E said customers should prepare for a shutoff lasting at least 48 hours. PG&E won’t restore power until inspections of de-energized lines are completed and any damage to the system repaired.

In Santa Cruz County, local government officials announced that a community resource center will open at 8 a.m. Sunday at Twin Lakes Church in Aptos. The church will provide electrical and powered medical device charging, information and water.

“We understand that a longer shutoff would be very difficult for our customers,” PG&E CEO and President Bill Johnson said in a statement. “We already are working to minimize the length, including amassing a force of field personnel from PG&E, plus contractors and other utility companies, to be ready to tackle the inspection, repair and restoration process as soon as the weather passes.”

The National Weather Service issued a red flag warning Friday morning, forecasting pending 15-30 mph winds with gusts of up to 35-55 mph late Saturday into Sunday morning for the Santa Cruz Mountains. At the same time, the Santa Cruz County Fire Department is warning that fuel and weather conditions are combining to make for an extremely dangerous period for fire risk. Officials are encouraging residents to exercise extreme caution and avoid activities that could lead to wildfires.

Affected customers were notified 48 hours in advance of a potential shutoff and will be again 24 hours before the power goes out, the company said.