A high surf advisory has been issued for the east shores of all isles from Kauai to Hawaii island, effective through 6 p.m. Thursday.

The National Weather Service expects surf of 8 to 12 feet along east shores due to a north-northeast swell, which should hold fairly steady through Wednesday.

Officials warn of strong, breaking waves and rip currents, making swimming difficult and dangerous.

Additionally, officials warned that this swell may produce surges in north harbors, including Hilo and Kahului, along with breaking waves near harbor entrances.

Mariners should use extra caution when entering or leaving port, and when mooring or launching vessels.

Officials have also issued a box jellyfish advisory after observations of the invertebrates — which have a powerful sting — on west shores, as well as Ala Moana and Waikiki beaches. Warning signs have been posted.

The forecast, meanwhile, includes partly to mostly sunny skies today, with scattered afternoon showers and highs from 79 to 84 degrees Fahrenheit.

Northeast winds of 15 to 25 mph are expected to continue through tonight when lows dip into the mid to high 60s.

The north-northeast swell is expected to slowly decline Thursday through the weekend.

Surf on south and west shores, meanwhile, should remain low, at 1 to 3 feet and 2 to 3 feet, respectively, today and Wednesday.

Breezy trades will continue into Wednesday, forecasters said, bringing showers to windward shores and slopes, then decrease late Wednesday and remain at moderate strength through Friday.