Planning a weekend at the beach or a walk along the Bay Trail? The National Weather Service is warning of high water and dangerous surf along the Bay Area shoreline from Friday into Tuesday.

Two alerts at once

A Coastal Flood Advisory runs from 9 a.m. Friday, Oct. 9, to 3 p.m. Tuesday, Oct. 13, for bayshore areas along San Pablo Bay, San Francisco Bay and Monterey Bay. The weather service says minor flooding is expected around the highest high tides, with water possibly covering low-lying parks, parking lots, roads and coastal trails. Only isolated road closures are expected, but the high water could cut off access to some low-lying beaches.

Separately, a Beach Hazards Statement covers the San Francisco Peninsula coast and the coastal North Bay, including Point Reyes National Seashore, from 7 a.m. Saturday to 2 p.m. Monday. Forecasters expect breaking waves up to 16 feet, an elevated risk of sneaker waves and strong rip currents.

When the water peaks

At the San Francisco tide gauge, the weather service's latest advisory text calls for high tides above normal each day around midday, with the highest, about 1.4 feet above normal, near 11:50 a.m. Saturday. Sunday's high is forecast around 12:18 p.m. and Monday's around 12:46 p.m. The predictions include storm surge on top of the astronomical tide, and timing varies by up to 90 minutes earlier or later around the coast and the bay.

The Chronicle reported that the elevated water and stronger northwest winds are the main local concerns, rather than the remnants of a storm heading toward Southern California.

How to stay safe

The weather service advises staying out of the water and off jetties, piers, rocks and other waterside structures, and never turning your back on the ocean. A sneaker wave can surge far beyond earlier waves and knock people off their feet even when they're just standing near the water, the Chronicle noted. If you drive near the shoreline around midday high tide, don't go through flooded roads.

The alerts overlap with Fleet Week's air shows along San Francisco's northern waterfront, so expect crowds there as well.