A high surf advisory is in effect for the north-facing shores of Hawaii island until Friday evening.

“An extra-large north-northwest 340 degrees swell combined with a large north swell 350 degrees will continue warning level surf for north- and west-facing shores of the smaller islands and advisory level surf for north-facing shores of the Big Island,” according to the National Weather Service in a statement.

Expect surf of 15 to 20 feet on the north shore of Hawaii island until 6 p.m. Friday.

EARLIER COVERAGE

A high surf warning for the north and west shores of most isles remains in place until 6 a.m. Friday.

The National Weather Service expects an extra large, north-northwest swell to build in quickly this morning, keeping the warning-level surf in place through tonight.

Surf of 30 to 40 feet is expected to rise rapidly along the north shores of Niihau, Kauai, Oahu, Molokai and Maui today. Surf of 18 to 22 feet is expected along west shores from Niihau to Molokai.

“Expect ocean water surging and sweeping across beaches, coastal benches, and lava flows creating the potential for impacts to coastal properties and infrastructure, including roadways,” said the advisory. “Powerful longshore and rip currents will be present at most beaches. Large breaking waves and strong currents may impact harbor entrances and channels causing challenging boat handling.”

The public should stay away from the shoreline of affected coasts, and be prepared for road closures.

Forecasters said “a mix of north and northwest swell energy impacting exposed beaches will likely support advisory-level surf by this weekend.”