Boaters off southern Oregon and far Northern California face a storm warning Friday morning and a second period of danger in the afternoon, when seas could build to 25 to 30 feet. The National Weather Service in Medford issued a hazardous seas warning that runs from 4 p.m. Friday to 1 p.m. Saturday, Pacific time.

The warnings cover waters from Florence, Oregon, south to Point St. George, California, and extend 60 nautical miles offshore. The storm warning runs until 9 a.m. Friday. Forecasters expect southerly gusts up to 55 knots and very steep seas of 15 to 19 feet. A gale warning follows until 4 p.m., with seas of 18 to 23 feet expected even as the wind eases.

The weather service says strong winds and steep seas can capsize or damage vessels and sharply reduce visibility. It advises mariners to stay in port or change course as conditions warrant and to secure their vessels. A second front could bring another round of strong winds late Saturday.

Check the bar before leaving port

Thursday evening Coast Guard reports published by the weather service listed restrictions on all recreational vessels and uninspected passenger vessels at the Siuslaw River, Umpqua River, Coos Bay and Chetco River bars. The Coos Bay report described steep swells of 12 to 14 feet in the larger sets. These are timed observations. Check the bar’s report time and call the Coast Guard number listed for that station before setting out.