PACIFICA (KRON) — The National Weather Service has issued a high surf advisory for coastal parts of the Bay Area for Friday.

The advisory will be in effect from through 4 a.m. Saturday and will cover the coastal North Bay, from Point Reyes to Big Sur.

The Coast Guard Captain of the Port San Francisco is warning beachgoers and operating boats of the dangers along the coast.

A storm is expected Friday afternoon and should produce wind speeds up to 21 miles per hour.

A swell is expected to produce waves and surf of 16 to 20 feet. Breaking waves at some deep-water spots could approach 30 feet.

The largest waves will continue through Saturday morning, weather service officials said.

There will be an increase in rip currents and sneaker waves. Beachgoers are warned there is a chance of being washed into the sea by a wave, and small vessels along the immediate coast may be swept toward coastal rocks.

Pacifica residents are already on edge because eroding cliffs are threatening their homes.