Surf's up — heads up.
The National Weather Service has issued a surf advisory for the Central California coast this weekend.
Weather officials say strong "sneaker waves" will start appearing on Friday afternoon. On Saturday and Sunday, waves could reach heights of 20 feet, along with strong rip currents.
NWS officials are concerned because the strong surf is happening on a holiday weekend when temperatures might rise close to 70 degrees.
The large waves are being caused by a strong storm out over the Pacific Ocean.