A high wind warning was also issued for counties along the northern and central coast. Peak winds ranged from 60 to 70 mph, the weather service said.
Many parks and other outdoor events or programs across the Bay Area were closed Wednesday due to wet and windy conditions. San Francisco cable car service has been halted as a precaution.
The California Highway Patrol previously warned drivers on Twitter to use “extra” caution on the roads.
“We responded to our first vehicle accident on I-280 in the rain today,” Cal Fire and the Redwood City CHP said Wednesday afternoon. “There were no injuries… Please slow down.”
In Sacramento, the weather service warned of a 10% to 25% chance of thunderstorms as the storm system moves inland. In addition to moderate to heavy rain and gusty winds, thunderstorms may also cause lightning and small hail.