Update at 5:11 p.m., December 20: A high surf warning is in effect for the coasts of Kona and Kohala on the island of Hawaii until 6 p.m. Sunday.

According to the National Weather Service in Honolulu, a series of strong northwest-north-northwest (315-330 degrees) swells will move through Hawaiian waters over the weekend and into early next week.

Surf of 10 to 14 feet is expected along the west coast.

There will be warning level surf along the north and west coasts of the smaller islands over the weekend, with a brief drop possible late Saturday and Saturday evening. The Big Island’s western shores are experiencing warning level surf, while the northern shores there are expected to have warning level surf.

Update from December 20th at 5:42 a.m.: The National Weather Service in Honolulu has expanded the Big Island’s high surf warning to include north-facing shores. The warning, which originally applied to the island’s west coast, has also been extended until 6pm on Saturday.

Surf of 15 to 20 feet is expected on the island’s north shore today, increasing to 18 to 24 feet tonight and Saturday. Surf of 6 to 8 feet is forecast for the west coast of the island.

A series of large waves from the northwest to north-northwest will continue to move through Hawaiian waters over the weekend and into early next week.

Advisory level surf is expected to continue until late Saturday afternoon.

Strong, breaking waves and strong currents make swimming and other ocean activities dangerous. Follow all advice from marine safety authorities.

If you have doubts, don’t go out.

National Weather Service forecasters in Honolulu expect the sharpest increase to occur Saturday night through Sunday.

This swell is expected to bring the biggest surf of the season so far to the North Shore on Sunday.

Original post from December 19th, 7:49 p.m.: A line of large waves from the northwest to north-northwest is moving through Hawaiian waters and will continue through Monday.

With overlapping wave pulses likely to result in warning-level surf along the Big Island’s western shores, the National Weather Service forecast office in Honolulu has issued a high surf advisory for the Kona and Kohala coasts, effective until 6 a.m. Saturday.

Large breaking waves of 7 to 10 feet are expected along the west coast, causing strong rip currents and making swimming and other marine activities dangerous.

The National Weather Service’s regional forecast discussion for Hawaii as of 3:49 p.m. Thursday said northwest energy was expected to reach the Big Island for a long period through this evening.

The public is advised to follow all advice from marine safety authorities. If you have doubts, don’t go out.