A powerful northwest swell will bring dangerously large waves to the north and west shores of most Hawaiian islands, with surf expected to peak Friday before gradually declining over the weekend.

A high surf warning is in effect from 6 p.m. today to 6 p.m. Friday for north and west-facing shores of Niihau, Kauai, Oahu, Molokai and the north-facing shores of Maui, according to the National Weather Service.

Surf is forecast to reach 25 to 35 feet along north-facing shores and 20 to 25 feet along west-facing shores. The large waves will create hazardous conditions, including strong currents and breaking waves in channel entrances, making ocean navigation dangerous. Weather officials advise staying away from affected shorelines and postponing any boating plans involving these channels until conditions improve.

The National Weather Service also warns of potential coastal overwash during high tide on Friday morning, which could affect low-lying areas.

Meanwhile, light southerly Kona winds will persist through the weekend due to stalled weather fronts northwest of Kauai, forecasters say. While rainfall is expected to be limited, some showers may develop over leeward areas of Kauai and Oahu. The muggy conditions will continue through Sunday, when tradewinds are forecast to return, strengthening by Tuesday and bringing an increase in windward showers.

In addition, vog from the ongoing Kilauea volcanic activity may continue to cause hazy skies across the islands, though emissions could decrease if volcanic activity slows.