Kauai County closed all north shore beaches from the Hanalei Pavilion to Kee Beach to swimming today because of high surf.
An earlier high surf warning has been downgraded to an advisory for north and west shores of Kauai County, Oahu and Molokai, and north shores of Maui through 6 a.m. Thursday.
The National Weather Service said waves should be diminishing to 15 to 20 feet along north-facing shores and 10 to 15 feet along west-facing shores.
On Kauai, lifeguards reported wave heights of up to 20 feet on north shores Wednesday morning.
Weather officials advised beachgoers to heed advice given by ocean safety officials.
Another northwest swell is predicted to arrive Friday and bring warning level surf Friday night through Saturday.