Starting Friday and running through Sunday, high temperatures will result in elevated heat risks and a heat advisory for much of the region starting Saturday at 10 a.m.
Interior areas of the East Bay will be the hottest, with highs ranging from the upper 90s to low 100s, while South Bay locations will be somewhat cooler with highs in the 80s to lower 90s.
Coastal areas will be cooler still with temperatures in the 60s and 70s.
"Saturday and Sunday will be the hottest days of this heat advisory period," said weather service meteorologist Anamaria Navarrete.
The heat will be compounded by low humidity levels in the 15% to 30% range that won't improve much in the overnight hours.
During this period, there will be "near critical" fire weather conditions, particularly for higher-elevation areas above the compressed marine layer, like the Diablo, Mayacamas and Santa Lucia mountain ranges.
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The most concerning fire conditions will happen during the afternoons and evenings, as sea breezes increase after sweltering hot days, according to the weather service.
Because wind gusts aren't currently forecast to peak above 15 mph to 20 mph, however, the risk of fire isn't expected to increase beyond the "near critical" or "elevated" levels.
People who live near the shore or who are heading to those areas to beat the heat should be wary of the marine forecast, which is calling for high tides and localized flooding in some areas.
"I want to emphasize the minor coastal flooding that areas along the bay shore and the North Bay will experience, and along the Central Coast," Navarrete said. "It is going to be hot and people may want to go to the water to cool down."
Beachgoers should be cautious of a robust southern swell coming out of the Pacific Ocean, which isn't going to be strong enough to warrant a beach hazard statement but will increase the likelihood of sneaker waves and rip currents, she said.
Temperatures are expected to drop throughout the region starting Monday.