Waves as high as 35 feet are expected starting today on northern shores from Niihau to Maui.

The National Weather Service in Honolulu has issued a high surf warning for those areas through Thursday afternoon. The warning also includes the western shores of Niihau and Kauai. A high surf advisory, meanwhile, is in effect for the western shores of Oahu, Molokai, Maui, and northern shores of the Big Island.

“A powerful low passing well north of the islands has generated a large north-northwest swell that will continue through Thursday,” forecasters said today. “Surf along north-and west-facing shores of Niihau and Kauai and along north-facing shores of Oahu, Molokai and Maui will be 25 to 35 feet.”

Surf along western shores of Oahu will be 12 to 18 feet, while the Big Island’s north shores will see 15-foot surf beginning today, forecasters predict.

A high surf warning indicates that large waves will make for dangerous swimming conditions and deadly rip currents, they said. Forecast estimates are for the height of the face of the waves.