South Swell In The Islands Continues - Hawaii

Moderate to locally fresh trade winds will continue to decline as a strengthen surface trough north of Kauai weakens the local pressure gradient. The trough will strengthen and expand over the islands Thursday night and Friday and linger into the weekend, disrupting the local winds. A strong disturbance aloft moving overhead will bring a threat for strong to severe thunderstorms mainly Friday into Saturday. These thunderstorms will have the potential to produce dangerous wind gusts, hail, and frequent lightning. Moderate east to southeast trade winds will gradually rebuild Sunday or Monday.

South: A long-lived south swell will affect the islands during the next several days. Low, long-period forerunners of 19 to 21 seconds have started to arrive at the local buoys this afternoon and will build over the area tonight. South shore surf is expected to rise near, or possibly to, the High Surf Advisory level of 10 feet during the peak of the swell Thursday afternoon through Friday. We have held off on issuing an advisory for now but will be watching the buoys closely tonight. This long-lived swell will gradually decline Saturday through Monday, with a small pulse of south-southwest expected to follow early next week.