UPDATE: Jan. 22, 9:45 p.m.
Surf is now expected to reach 35 to 50 feet along north facing shores of Niihau, Kauai, Oahu, Molokai, and Maui. Surf of 25 to 35 feet along west facing shores of Niihau, Kauai, Oahu, and Molokai, forecasters said.
“Expect ocean water surging and sweeping across beaches, coastal benches, and lava flows creating the potential for impacts to coastal properties and infrastructure, including roadways,” the weather service said in a news release.
Most beaches in the affected area will see powerful longshore and rip currents, while large breaking waves and strong currents could impact harbor entrances and channels.
UPDATE: 3:45 p.m.
A high surf advisory for north and west shores of Niihau, Kauai, Oahu, and Molokai, and north-facing shores of Maui has been extended to early Sunday morning.
The warning has been expanded to include west shores of the Big Island as a west-northwest swell continues to build.
According to the latest forecast, surf will reach up to 30 to 40 feet along north-facing shores and 20 to 30 feet along west-facing shores of smaller islands.
The north shores of most islands could see surf up to 35 feet as a west-northwest swell rolls in and tradewinds pick up.
The National Weather Service placed north and west shores of Oahu, Kauai, Molokai and Niihau, and the north shores of Maui under a high surf warning through 6 p.m. Saturday.
A west-northwest swell is expected to build down the island chain, peaking Saturday, according to the weather service. Surf up to 25 to 35 feet is expected on north shores and up to 18 to 25 feet on west shores.
Forecasters say to expect ocean water occasionally sweeping across portions of beaches, strong breaking waves and longshore and rip currents. Breaking waves may occasionally affect harbors, making navigating the harbor channel dangerous.
Tradewinds are expected to increase to moderate strength through Saturday, forecasters said.