The National Weather Service has issued a high surf warning for north and west shores of Niihau, Kauai and Oahu.

Surf heights along north-facing shores are expected to rise to the advisory level of 10 to 15 feet by late this afternoon and reach the warning level of 20 to 25 feet late tonight.

West-facing shores will see surf with wave faces of 8 to 12 feet by late this afternoon, and 15 to 20 feet later tonight, forecasters said.

A powerful low pressure system northwest of the islands has generated a large swell that will arrive along exposed north and west shores late this afternoon, the Weather Service said.

The swell will build throughout the evening and will exceed warning levels on Niihau, Kauai and Oahu by late tonight, forecasters said.

The swell, and resulting high surf, are expected to last through Friday.

The high surf warning will remain in effect through 6 p.m. Friday.