Heat advisory in effect as mid-week heat wave grips Bay Area, Northern California
The hottest days of the week in the Bay Area and Northern California began Wednesday with heightened fire risk and inland temperatures expected to reach triple-digits or near-triple digits into Friday.
The National Weather Service said a Heat Advisory was in effect at 11 a.m. Wednesday through 11 p.m. Thursday for the Marin and Sonoma Coastal Ranges, North Bay interior mountains, East Bay Hills and interior valleys, the Santa Clara Valley and Eastern Santa Clara Hills. The advisory also covered the Santa Cruz Mountains, Santa Lucia Mountains, San Benito Mountains, Interior Monterey County, and a wide swath of the Central Valley.
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Peak high temperatures of 95 to 105 degrees were expected across these regions into Thursday. Interior Monterey and San Benito Counties have the potential to remain 10-20 degrees above normal through Friday and the Weather Service said the Heat Advisory may need to be extended into Friday night for this area.
In San Francisco, especially across the eastern half of the city, the heat advisory was in effect through 7 p.m. Wednesday and temperatures were expected in the 80s.
Farther south, an excessive heat warning for dangerous hot conditions was in effect from 11 a.m. through 8 p.m. Friday for portions of Southwest California as far north as the Southern Salinas Valley. The Weather Service said highs of 95 to 110 degrees are expected with little to no overnight relief.
The "Unofficial end to Summer" was yesterday, but today's maximum temperature map says otherwise. Interior locations with little to no marine layer influence were 100°F+. #cawx pic.twitter.com/1MyX9LS3vB
— NWS Bay Area 🌉 (@NWSBayArea) September 4, 2024
The heat is accompanied by near-critical fire weather conditions because of poor relative humidity recoveries across interior locations and higher elevations, the Weather Service said. Temperatures for the next two days will be around 20 degrees warmer and relative humidities about 60% drier than yesterday.
Moderate HeatRisk and near critical fire weather conditions will continue through at least tomorrow. Follow these safety tips to keep yourself and others safe. #CAwx pic.twitter.com/bQJTd2g08e
— NWS Bay Area 🌉 (@NWSBayArea) September 4, 2024
The Weather Service said the heat advisory meant a moderate heat risk would affect individuals sensitive to heat and those without effective cooling or adequate hydration.
A gradual cooling trend will kick off by Friday and by Saturday, temperatures were expected to return to near normal or slightly below normal except for higher elevations.