Oh fun. The National Weather Service has issued a totally tubular high surf advisory, which starts Tuesday night "due to an incoming swell that is expected to create waves up to 20 feet high." Can you say, bitchin'?
But in all seriousness, the swell "will create powerful waves up to 20 feet high and strong rip currents in the surf zone." Which is to say, you should be extraordinarily careful if you plan on riding a few waves. Which, really, you shouldn't unless you're a season surfer on par with Spicoli.
Said advisory affects San Francisco, Santa Cruz, San Mateo, Marin, Monterey, Contra Coast, Napa, Sonoma, Santa Clara, and Alameda counties.