High Surf Advisory issued December 20 at 2:27AM PST until December 22 at 4:00PM PST by NWS San Francisco CA

* WHAT…Expect large westerly swell with breaking waves 15 to 18
feet, including breakers near 20 feet possible along favored
west facing beaches.

* WHERE…San Francisco, Coastal North Bay Including Point Reyes
National Seashore, San Francisco Peninsula Coast, Northern
Monterey Bay and Southern Monterey Bay and Big Sur Coast.

* WHEN…From 6 AM Saturday to 4 PM PST Sunday.

* IMPACTS…Dangerous swimming and surfing conditions and
localized beach erosion. Large waves can sweep across the
beach without warning, pulling people into the sea from rocks,
jetties and beaches. Sudden immersion in cold water can result
in cold water shock even for the most experienced swimmers.
Cold water shock can result in dramatic changes in breathing,
heart rate and blood pressure, greatly increasing the risk of
drowning in rough open waters.