The heat is gone, but the Bay Area coast has a new problem this holiday weekend: unusually high water. The National Weather Service has a Coastal Flood Advisory in effect for the San Francisco shoreline until 3 p.m. Tuesday, plus a Beach Hazards Statement from Saturday morning through Monday evening.
How high the water gets
At the San Francisco tide gauge, forecasters expect high tide to run about 1.4 feet above normal, reaching 7.3 feet, at 11:50 a.m. Saturday and again at 12:18 p.m. Sunday. Monday's high tide, at 12:46 p.m., is forecast at 1.2 feet above normal, and Tuesday's, at 1:14 p.m., at 1.1 feet above normal. The weather service says those numbers include up to 1.2 feet of storm surge stacked on top of the normal tide.
That can mean up to 1.4 feet of water in low-lying areas near shorelines and tidal waterways. The advisory warns of flooding in parking lots, parks and roads, with only isolated road closures expected, along with flooded coastal trails and some low beaches cut off at high tide. High tide can arrive up to 90 minutes earlier or later depending on where you are along the coast and inside the bay.
Dangerous surf at the beach
The beach hazards part of the warning is about the ocean side. Forecasters expect breaking waves up to 16 feet, with a higher risk of rip currents and sneaker waves, the surprise surges that can run far up the sand and knock people off their feet. The weather service's advice is to stay off jetties, piers and rocks, stay out of the water and never turn your back on the ocean.
In its Saturday briefing for local agencies, the weather service listed coastal flooding as a risk for the North Bay, San Francisco and the Peninsula from Saturday through Wednesday, along with a sharp cool-down and a chance of light rain on the north Central Coast early next week.
Then the sun takes over
The cooler air won't last long. The weather service's point forecast for San Francisco calls for sunny skies and a high near 62 on Saturday and 64 on Sunday, then highs around 67 Monday through Wednesday. By Thursday the city is forecast to reach about 75, and Friday about 77, with mostly clear nights in the mid-50s.
If you're heading to the waterfront for Fleet Week or a holiday beach day, the practical advice is simple: check tide times before parking near the shore, and give the surf a wide berth.