A record-breaking heat wave is expected to lose a bit of its sizzle on Friday even as it continues to bake much of the Bay Area.

Still, relief is on the way. It’s just not moving as quickly as National Weather Service forecasters anticipated.

“We are watching a surge of the marine stratus clouds coming up from Southern California,” meteorologist Drew Peterson said Friday morning. “At this point, it’s moving a bit slower than we hoped. So the cooling may not come as quickly as we anticipated (Friday).”

Temperatures are expected to pack only slightly less of a punch than they did Thursday, when heat records throughout the region fell. The weather service said it’s not anticipating record temperatures on Friday but that the overall cooling off may show only 2-3 degrees in some areas, instead of the 5-8 degrees that had been anticipated.

“It’s going to be cooler as a whole in the region today,” Peterson said. “But it’s still going to be extremely hot.”

An excessive heat advisory remained in effect until 9 p.m. Friday for the East Bay hills and valleys, as well as the North Bay Mountains. Temperatures in those areas still were expected to reach or exceed 100 degrees, according to the weather service.

The California Independent System Operator has implemented a statewide Flex Alert from 6-9 p.m., the second straight evening that customers are being asked to conserve energy during the maximum usage times.

A Spare the Air remained in place for the second straight day, with wood burning banned and residents urged to stay inside.

On Thursday, Brentwood claimed the hottest spot in the Bay Area, reaching 109 degrees. Concord and Livermore each reached 107 degrees, the latter surpassing that city’s 60-year-old heat record of 104.

Gilroy (106), Santa Rosa (104), San Rafael (103), Kentfield (103), Redwood City (103) and King City near Monterrey (101) also set records, according to the weather service.

Also on Thursday, San Jose maxed out at 95 degrees, Oakland at 87, San Mateo at 85 and San Francisco at 80.

The overnight temperatures stayed warm, Peterson said, with the reading a degree or two warmer than the lows the previous evening.

“The hot air is still present, and it’s just kind of been settling,” Peterson said. “We’re starting to see a tiny bit of that marine influence, and that should only increase as those stratus clouds continue to move north.”

Peterson said temperatures on Saturday should be at least five degrees cooler in most area of the region, and possibly 8-10 in some areas.

Please check back for updates.