First major winter swell expected this weekend along north, west shorelines

The first major winter swell of the season looks like it will arrive on Kaua‘i’s doorsteps this weekend, generating monster waves, with sets that could at times exceed 50 feet along northern shores.

National Weather Service forecasters at the Honolulu forecast office reported Wednesday afternoon that an extra large west-northwest to northwest swell is expected to rapidly fill in Saturday evening and peak Saturday night into Sunday, likely producing giant warning-level surf of 40 to 50 feet along north-facing shores and 25 to 35 feet along west-facing shores.

A high surf warning is anticipated for for north- and west-facing shores of Kaua‘i, with forecasters having high confidence in the massive predicted surf, with occasional larger sets along northern shorelines.

This surf event could lead to coastal and harbor impacts for exposed northern and western shorelines, especially during high tides, which will move in near midnight and noon Saturday night and Sunday.

Expect ocean water surging and sweeping across beaches, creating the potential for impacts to coastal properties and infrastructure, including roadways.

There is moderate forecast agreement that waves will wash across roads near shorelines exposed to the swell at high tide.

Powerful longshore and rip currents will be present at most Kaua‘i beaches as well.

Large breaking waves and strong currents could also impact harbor entrances and channels, causing challenging boat handling.

Forerunners will begin arriving as early as Saturday afternoon and rapidly build through Saturday night.

Forecasters advise the public to keep an eye on the statewide surf forecast for the latest surf heights as the event nears.

Peak swell heights of 15 to 20 feet are expected Saturday night into Sunday, with a peak swell period of 16 to 20 seconds.

Top wave heights are expected late Saturday night and into Sunday morning, with warning level surf looking possible through Monday along shores with northern and western exposure.

The swell should begin to gradually decline Sunday afternoon and continue a downward trend through the middle of next week.