An unseasonable swell will keep surf advisory levels through this afternoon and keep southern shores under a high surf advisory until 6 p.m., the National Weather Service said. A new northwest swell may also produce advisory level surf along most north and west shorelines today.

The south swell was generated by a powerful storm southeast of New Zealand a week ago and will bring surf 6 to 8 feet.

Surf along the north shores of Oahu, Kauai, Molokai, Niiahu and Maui is expected to build to 12 to 16 feet overnight, and surf along the western shores of those islands, except for Maui, will be 8 to 12 feet.

Surf along east facing shores will persist at 1 to 3 feet through today.

Another large northwest swell arriving late Wednesday may produce surf heights near the high surf advisory threshold Thursday.