Flood watches and warnings are in effect across coastal and mountain areas in California as of Sunday night, with forecasters warning of more heavy rainfall from a large storm moving south.
Potentially strong thunderstorms have been forecast for Monday, the National Weather Service said.
Some areas, such as Santa Barbara and Ventura, are expected to receive up to 8 inches of rain on Sunday night or Monday morning, it added.
Marin, Napa, and Sonoma were expected to experience flooding on Sunday night, the service warned.
A mild cold front late Saturday has been followed up by a more destructive storm system that will gain strength into early Monday, meteorologist Brayden Murdock from the National Weather Service office in San Francisco said.
“The winds are here and getting stronger, and the rains will follow quickly,” Mr. Murdock said Sunday afternoon.
The arrival of the powerful storm has also led forecasters to warn of possible hail, strong winds, and even brief tornadoes over the next few days.
Wind gusts ranging from 35 to 50 mph were recorded in the Bay Area on Sunday night, with a wind advisory remaining in effect until 4 a.m. on Tuesday.
California’s central coast is at risk of “significant flooding,” with up to 5 inches of rain predicted for many areas, the weather service said.
The state is still recovering from the impact of the devastating atmospheric river that parked itself over Southern California earlier this month, turning roads into rivers, causing hundreds of landslides, and killing at least nine people.
The rainfall isn’t expected to be as heavy on Monday as the conditions are just short of being another atmospheric river.
“It’s not the ideal setup for an atmospheric river, but it does have some of the characteristics,” including a band of subtropical moisture bringing up the rear of the storm, Mr. Murdock said. “Otherwise, it’s just a cold front.”
Motorists are urged to avoid mountain routes. The weather service said that several feet of snow are possible at elevations above about 6,800 feet (2,070 meters) across the Sierra Nevada.
“Consider completing Sierra travel during the day Sunday, or rescheduling to later next week,” the weather service office in Reno, Nevada, said. The office issued a backcountry avalanche watch for the greater Lake Tahoe area and the eastern Sierra in Inyo and Mono counties.
The California Governor’s Office of Emergency Services activated its operations center Saturday and positioned personnel and equipment in areas most at risk.
