A high surf warning has been issued for the north- and west-facing shores of most isles, effective as early as midnight and lasting through 6 p.m. Friday.

The National Weather Service is expecting a “significant, extra large northwest swell” to arrive late tonight, starting with Kauai, then rapidly build down the island chain Thursday.

The warning has staggered start times as it makes its way down the isle chain:

>> Starting midnight tonight: Kauai, where surf is expected to rapidly rise to 40 to 50 feet along north shores, and 25 to 35 feet along west shores. Effective until 6 p.m. Friday.

>> Starting 6 a.m. Thursday: Oahu and Molokai, where surf is expected to rise to 40 to 50 feet along north shores and 25 to 35 feet on west shores. For Maui, surf of 25 to 35 feet is expected on north shores. Effective until 6 p.m. Friday.

>> Starting noon Thursday: Hawaii island, where surf is expected to rise to 20 to 25 feet along north shores of the Hamakua coast. Surf is expected to rise to 8 to 12 feet along west shores, including Kona and Kohala. Effective until 6 p.m. Friday.

“This swell will result in surf rapidly rising to warning levels along most north and west facing shores,” said NWS forecasters. “In addition, a swell of this size will adversely impact coastal areas, especially during high tide Thursday evening.”

It’s expected to peak through Thursday night, then gradually decline Friday and Saturday.

Officials said preparations should be made for “significant coastal impacts” as ocean water runs up and inundates beaches, potentially affecting properties and roadways.

The impacts will be very high, with ocean water surging and sweeping across beaches, and powerful longshore and rip currents present at most beaches.

The public should stay away from the shoreline along affected coasts, be prepared for road closures, and postpone entering or leaving channels affected by the high surf until it subsides.