Overview
- A resurgent marine layer is expected to push cool, foggy air into coastal and bay-adjacent zones Tuesday and Wednesday, producing a short-lived midweek cooldown.
- The National Weather Service issued a heat advisory for Monday for parts of the Bay Area with expected highs of 95–105°F in inland valleys and hills.
- Inland areas, especially the East Bay and Tri-Valley, are forecast to be the hottest with mid-to-high 90s and minimum relative humidities below 30 percent around Altamont Pass and Mount Diablo, conditions that dry fuels and increase fire spread potential.
- The Bay Area Air Quality Management District expects mostly good to moderate air quality this week, but local fires in Mendocino, Sonoma and Santa Clara counties and large fires in Oregon could send intermittent smoke into the region and reduce visibility in places.
- Forecast models show the western high-pressure ridge rebuilding by late week, which is likely to restore hotter, drier, and breezier conditions with a renewed risk of triple-digit inland temperatures and elevated fire weather through the weekend, so officials urge hydration and caution with ignition sources.