San Francisco Bay Area weather: flood watch issued ahead of storm

A strong storm headed toward California has led authorities to issue a flood watch for a vast area covering the Bay Area and Central Coast that takes effect Saturday.

Heavy rains are expected to commence Saturday afternoon. The storm is tracking to have the most impact on the Santa Cruz mountains, but the flood watch stretches from the North Bay coast to Big Sur and stretches into the hills and valleys of inland areas.

There will be moderate to heavy rainfall, the National Weather Service predicts, which could cause rivers to rapidly rise and spill. "This could result in nuisance as well as minor flooding," the NWS said. 

Sonoma County is closing at least five roads highly-prone to flooding ahead of the atmospheric river. You can find information on road closures in Sonoma County, here.  

The heaviest rain will fall from Sunday afternoon until Monday morning.

San Francisco, the Peninsula and areas close to the Bay will get 1.5 to 4 inches of rain. Hilly areas in the North Bay can expect 5 inches. The Santa Cruz mountains may get 7 inches of rain.

This storm will include stronger wind gusts than the atmospheric river that washed overhead on Wednesday. San Francisco, the Peninsula's coast, Santa Cruz mountains and the northern end of the Monterey Bay are also under a high wind warning from Sunday 4 a.m. to 10 p.m. Gusts reaching speeds of 60 mph could happen in the Santa Cruz mountains.

The flood watch is in effect from 4 p.m. Saturday until 10 a.m. Monday.

The storm will have a major impact on other parts of California. The Lake Tahoe area and much of the Sierra Nevada range will get buried by significant amounts of snow. Southern California is bracing for heavier rain than the Bay Area. The wettest sites may see 9 inches of rain.

Pacific Gas and Electric is mobilizing ahead of the storm. 

"The storm is looking to be stronger than the Wednesday/Thursday system of this week, with gusty winds expected for large swaths of the territory accompanied by periods of heavy rain," said PG&E meteorologist Evan Duffey. The utility has updated their online outage center if outages do occur. 

The governor's office has increased personnel ahead of the storms and has activated its State Operations Center, Flood Operations Center, Caltrans Emergency Operations Center and the Medical Health Coordination Center. 

Meanwhile, on Friday, Gov. Gavin Newsom added Monterey, San Mateo, and Santa Cruz counties to his state of emergency proclamation. You can find a copy of that proclamation here