A heat advisory will come into force across much of the San Francisco Bay Area on Saturday, with inland temperatures expected to climb as high as 103°F (39°C) and persist through Monday night.
The National Weather Service said the advisory would begin at 11am on Saturday and remain in place until 10pm on Monday. It covers the San Francisco Bay shoreline, East Bay and South Bay, Santa Clara Valley, parts of Sonoma, the Santa Cruz Mountains, interior Monterey and San Benito counties, and the southern Salinas Valley.
Forecasters expect widespread moderate heat risk, with pockets of major risk in inland areas. Temperatures are forecast to reach between 95°F and 103°F (35°C to 39°C) in the valleys, while bayside communities could see highs of 80°F to 92°F (27°C to 33°C).
Coastal areas will be cooler, reaching about 68°F to 75°F (20°C to 24°C), although morning sea fog is expected to clear quickly. Dense, locally blinding fog could affect coastal roads before sunrise, particularly around Monterey Bay and the Central Coast.
Overnight conditions may offer limited relief in some higher areas, where temperatures are expected to remain in the upper 60s to mid-70s Fahrenheit. The weather service has urged people to drink plenty of water, avoid strenuous activity during the hottest part of the day and check on relatives and neighbours who may be vulnerable to extreme heat.
Light onshore winds are expected across the region, with isolated afternoon gusts of 20 to 25mph through wind-prone gaps and the northern Salinas Valley. Forecasters said the weak airflow could allow pollution to become trapped near the ground, contributing to poor air-quality conditions through Sunday.
