A high-surf warning for shores on most islands is in effect until 6 p.m. tomorrow, according to the National Weather Service.

Surf along north- and west-facing shores of Niihau and Kauai, and northern shores of Oahu, Molokai and Maui should reach 25 to 35 feet, forecasters said yesterday.

Surf on western shores of Oahu and Molokai should reach heights of 15 to 20 feet.

The waves are being generated by a northwest swell that was expected to peak late yesterday but continue at least through today, according to forecasters.

The warning also includes western shores of the Big Island.

The high surf may produce dangerous swimming conditions and deadly rip currents, authorities said.