A new weather front is set to bring warm temperatures and elevated fire danger to parts of the Bay Area later this week, prompting the National Weather Service to issue a red-flag warning for the East Bay hills and interior mountains of the North Bay. The warning, citing high winds and low relative humidity that could rapidly worsen any small fire, will be in effect from 11 p.m.
Wednesday to 9 a.m. Thursday.
In response, Pacific Gas and Electric (PG&E) has indicated that it may implement public safety power shutoffs in portions of Sonoma, Napa, and other Northern California counties to reduce the risk of wildfires sparked by power lines. The weather pattern shift, driven by high pressure building over the West and a low-pressure trough moving east, will bring offshore winds and drying conditions.
Meteorologist Karleisa Rogacheski of the National Weather Service explained, "We've got the pattern change in full swing. High pressure building over the West and the low-pressure trough moving east will allow for some warming and drying with some offshore winds." This combination is expected to push temperatures into the high 90s and possibly 100 degrees by Thursday in the hottest areas, including the far East Bay and parts of the North Bay.
The South Bay will not be far behind, with Morgan Hill and Redwood City potentially reaching the 90s. Some coastal areas, including the Peninsula and San Francisco, could see temperatures in the 80s on Thursday, which may set records.
"We expect Thursday to be the hottest day," Rogacheski said. The cooldown will be gradual, with temperatures remaining in the 90s through Friday in the far East Bay, South Bay, and North Bay mountains.
By Sunday, highs are expected to drop to the low 80s. The trough also brought light drizzle and minimal rain to some coastal areas Monday evening, but no significant precipitation is expected.
Residents in affected counties should prepare for possible power shutoffs and take precautions against fire danger.