Update 3:55 p.m.
A high surf advisory is in effect for the north- and west-facing shores of most islands until 6 a.m. Saturday.
The National Weather Service in Honolulu issued the advisory just before 4 p.m. today. It replaces an earlier high-surf warning.
A west-northwest swell is expected to bring surf as high as 18 to 22 feet overnight, lowering to 15 to 20 feet on Friday.
The advisory includes the north- and west-facing shores of Oahu, Niihau, Kauai and Molokai, and the north-facing shores of Maui.
A high surf warning is in effect for most of the Hawaiian islands until 6 p.m. today.
The National Weather Serviced issued the warning for the north shores on Oahu and Maui, north and west shores of Kauai, Niihau and Molokai and west shores of the Big Island.
Forecasters said a large west-northwest swell is expected to bring waves of 20 to 25 feet to Oahu, Maui, Kauai, Niihau and Molokai while 10- to 15-foot waves are expected for the Big Island.
The weather service said the swell is expected to subside later today, however, another large swell is expected to roll in tonight and Friday.
Forecasters warned beachgoers of dangerous currents and shore breaks.
A high surf advisory is also in effect for the west shores of Oahu.