(BIVN) – The National Weather Service in Honolulu has issued a High Surf Advisory for the south-facing shores of all the Hawaiian islands, in effect through Thursday.

Surf heights of of 7 to 12 feet are expected.

The long-period south swell will build today, peak tonight, and gradually diminish on Thursday, forecasters say. “This surf was generated by a storm in the southern hemisphere and is not associated with Hurricane Darby,” the Hawaiʻi County Civil Defense stated in a Wednesday morning message.

On Hawaiʻi island, officials say the affected area stretches from Keahole Point in North Kona, south through Kaʻū to Cape Kumukahi in Puna.

Due to the High Surf Advisory, Civil Defense said the following are issued:

• Expect strong breaking waves, shore break, and rip currents making swimming difficult and dangerous.
• Beach-goers, swimmers, and surfers should exercise caution and heed all advice given by Ocean Safety Officials.
• Beaches may be closed without notice.

The National Weather Service noted that “extreme high tides the next couple of afternoons could lead to salt-water flooding of beaches and low-lying shoreline areas.”