Surf up to 40 feet high is forecast for Oahu’s North Shore and other major islands today.

The high surf warning, in effect starting at 6 a.m., also extends to the north and west shores of Kauai, Niihau, Oahu and Molokai, and the north shores of Maui and the Hawaii island, the National Weather Service said.

A high surf advisory is in effect for the west shores of Maui.

The warning extends at least through 6 p.m. Tuesday, the weather service said.

“A large north-northwest swell will build rapidly Monday, bringing warning-level surf to exposed north- and west-facing shores of Kauai County in the morning,” the agency said on its website. Oahu and Maui County will be hit during the day, and Hawaii island in the evening, forecasters said.

Surf in the 30 to 40 foot range can be expected on the north and west shores of Kauai, Niihau and Molokai and the north shores of Oahu and Maui. Waves from 20 to 30 feet are predicted for the west shore of Oahu and north shores of the Big Island, the weather service said.

The weather service predicted “very strong breaking waves and strong longshore and rip currents.” Navigating harbor channels also could prove hazardous, the agency said.