A high surf advisory has been issued for the south facing shores of all Hawaiian isles, effective through 6 p.m. Thursday.

The National Weather Service says a long-period south swell is expected to build today, peak tonight, and then gradually diminish on Thursday.

Surf of 7 to 12 feet is expected for south facing shores on all islands.

Officials warn of strong, breaking waves, shore break, and strong rip currents, which will make swimming difficult and dangerous.

In addition, extreme high tides during afternoons in the next few days could lead to salt-water flooding of beaches and low-lying shoreline areas.

Beachgoers, swimmers, and surfers should heed all advice from ocean safety officials.

Forecasters are expecting a larger and longer-period south swell late Friday through the weekend.