A large northwest swell has prompted a high-surf warning for areas of Oahu, Kauai, Molokai, Niihau, Maui and the Big Island until 6 p.m. Tuesday

Forecasters predicted surf of 18 to 25 feet along north- and west-facing shores of Kauai and Niihau, and north-facing shores of Oahu, Molokai and Maui; 14 to 20 feet along west-facing shores of Oahu and Molokai; and 10 to 15 feet along west-facing shores of the Big Island.

The National Weather Service warns of ocean water surging and sweeping across beaches, impacts to coastal properties and infrastructure, powerful longshore and rip currents at most beaches, and large breaking waves and strong currents at harbor entrances and channels.

Meanwhile, a high-wind warning for the summit areas of the Big Island has been extended through 6 p.m. Monday as an upper-level trough approaches the island.

Westerly winds are expected to reach 50 to 75 mph, with localized gusts of up to 85 mph, according to the National Weather Service.

A winter weather advisory also remains in effect until noon on Monday for Big Island summit areas above 12,000 feet.

The advisory notes the possibility of snow and freezing fog. Snow accumulations could reach up to 4 inches with a coating of ice. 

Temperatures are expected to dip to the upper 20s and lower 30s.