This weekend will present the Bay Area with an extreme version of its typical summer battle between foggy marine air and inland heat.
While a heat advisory is in effect for triple-digit temperatures in the interior valleys, parts of San Francisco may not see more than a few hours of sun as the fog caps temperatures in the 60s. Outside Lands attendees should pack layers.
This contrast is expected to be most stark Saturday and Sunday and will stem from a strong high-pressure system over Nevada. Beneath the system, hot air will rise and cause an area of low pressure to form near the ground each afternoon. The same phenomenon will take place in California’s Central Valley and induce cool, dense ocean winds that rush toward the low pressure. The Central Valley is too far away from the coast to catch the sea breeze until the early evening when temperatures are already dropping, but the winds provide an afternoon cooling effect for Bay Area valleys that are closer…