Bay Area residents faced the third day of searing temperatures Saturday as the overwhelming heat wave prompted increased fire risk and the threat of continued rolling blackouts across the state.

The National Weather Service issued a Red Flag Warning for the region in anticipation of increased wildfire risk, concerned that lightning from southern thunderstorms could ignite flames. Around the state, meanwhile, about 220,000 people reeled after losing power Friday thanks to increased electricity demand.

And California Independent System Operator, the non-profit organization that runs the state’s power grid, issued an alert effective from 5 to 9 p.m. Saturday, warning that energy demand may exceed supply, and urging consumers to conserve power during those hours.

“Conditions remain challenging because of extremely hot weather. The temperatures look slightly better today, but because overnight temperatures were still higher than normal, we anticipate demand to be high again,” spokeswoman Anne Gonzales wrote in an email. “We are not planning to call for rotating power outages at this time, but system conditions are always subject to change.”

Temperatures dipped slightly lower across the region compared to Friday’s sky-high records, but still scraped the mid-80s in San Francisco by midday and the low 100s across inland parts of the Bay Area, according to the NWS.

The sweltering heat is likely to continue for days as high pressure from the northwest continues bringing hot air into California, said meteorologist Anna Schneider.

“The high pressure’s not going anywhere anytime soon — looks like we’ll be in this heat pattern for the next week,” Schneider said, adding, “This is a pretty long-duration event.”

On Friday, a dozen Bay Area cities tied or set new daily heat records as temperatures soared across the Bay Area, according to the National Weather Service. Gilroy topped the list with a high of 107 degrees, tying a record set in 1996. The mercury shot to 106 degrees in Santa Rosa, handily beating the record of 101 set last year. Santa Cruz shattered its 114-year-old record of 96 degrees with a high of 105.

Thousands of people lost power in hour-long rotations throughout the day after the nonprofit California Independent System Operator, which runs the state power grid, issued a grid warning. All customers were expected to have power back by 11 p.m., according to utility PG&E.

Jason Green contributed to this report.

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