The National Weather Service has issued coastal flood and high surf warnings for the Bay Area, predicting dangerously high waves beginning tonight.

The warnings will be in effect today from 10 p.m. to 4 a.m. Thursday for the entire coastal Bay Area.

Offshore swells will create waves of at least 20 feet, according to the National Weather Service. Forecasters expect these forceful waves to batter local shorelines, creating deadly rip currents and dangerous swimming conditions. Beach erosion is also a possibility under these conditions.

The coastal flood warning means floods are imminent or already occurring, according to the National Weather Service. Early this morning, the California Highway Patrol reported standing water in Marin- and Redwood City-area roadways. Residents along the coast should be alert for rising water, according to the weather service.

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