Scattered showers and cool temperatures were expected in the Bay Area Monday as an unusual late season weather system moved across the region.
Colder temperatures will remain in most areas of the region, even as rain retreats later in the day Monday. There will be a chance of thunderstorms through late afternoon.
The system also brought snow to the Sierra Nevada early Monday. Early morning snow accumulations in the Sierra have occurred at locations including on Interstate 80 at Donner Summit.
Flash flooding could occur in the Sacramento Valley and northern San Joaquin Valley, weather officials said.
Drier conditions will prevail Tuesday and through the week, with gradual warming up to 65 on Tuesday and 68 on Wednesday in San Francisco and highs of 71 on Tuesday and 75 on Wednesday in Walnut Creek.