As temperatures prepared to crank up to well past 100 degrees in parts of the Bay Area on Tuesday, the National Weather Service delivered news that hardly offered any relief.
“Nothing is pushing this high pressure,” NWS meteorologist Nicole Sarment said. “It’s just staying stagnant and showing no signs of breaking down anytime soon. So this is going to be going on a while, maybe longer than we thought.”
The weather service extended an excessive heat warning for another day. The warning, which went into effect at 11 p.m. Monday now runs through Sunday night at 8 p.m. Sarment said. The conditions are such that the warning could be extended into Monday, she said.
A red flag warning for severe fire conditions also went into effect at 11 p.m. Monday in the East Bay Hills, Marin Coastal Range, Sonoma Coastal Range and the Santa Cruz Mountains. Wind gusts are expected to be at least 25 mph and will combine with the low humidity and heavy grasses to make for the dangerous conditions.
PG&E said it started shutting off power in parts of Napa, Solano, Lake, Yolo, Colusa, Shasta, Glen and Tehama counties to relieve some pressure on the state’s power grid.
Tuesday started with a Spare the Air Alert in place because of smoggy conditions that could make it hard to breathe for small children, infants, elderly people and those with heart and respiratory conditions. Air quality is expected to be unhealthy for that group at times Tuesday.
Forecasters and public safety officials also emphasized again the dangers of using fireworks as the Fourth of July Holiday approaches. Fire officials said fireworks were suspected in a vegetation fire late Monday in the Oakland hills that burned two acres near Centennial Drive and Grizzly Peak. That fire did not threaten any homes, officials said.
“We really can’t emphasize enough how dangerous it’s going to be to use fireworks this year,” Sarment said. “Whether you’re in a red-flag area or not, just leave them alone. It’s a very dangerous idea.”
The blast of heat — already forecast to be the longest and hottest stretch for the region since the days surrounding Labor Day in 2022 — was expected to jump 10-12 degrees from the previous 24 hours in the hottest places on Tuesday and could jump two or three more degrees from there on Wednesday, according to forecasters.
At 7 a.m., it was already 81 degrees in Brentwood in far east Contra Costa County, where the temperatures were expected to peak at 110 degrees. In Concord, the thermometer already was 70 degrees and expected to reach 108. The South Bay was heating more slowly; in Morgan Hill, it was 60 degrees at 7 a.m. but expected to get to 101. San Jose was forecast to reach 99.
Sarment said warmer-than-normal temperatures also will permeate cities closer to the water but that those cities will be significantly cooler than those inland. Oakland and San Mateo are expected to get to 89 on Tuesday, and San Francisco is forecast to be 79.
About the only chilly weather in the region will be in Half Moon Bay, where the mercury is expected not to exceed 69.
All of it follows a Monday that normally would be considered a mini spike in the heat. Brentwood’s high temperature was 103, Concord reached 101, Morgan Hill got to 96 and San Jose 91. San Mateo’s high was 78, Oakland was 74 and San Francisco was 74, according to the weather service.
Sarment said that in addition to the heat, minor flooding created from tide anomalies could be an issue for some areas of coastal Marin County.