Swell Matrix

Area Forecast Discussion

National Weather Service Honolulu Hi

820 pm hst Sun jul 19 2026

Synopsis

Moderate to locally breezy trades will continue this week as high pressure remains anchored well north of the state. A relatively dry and stable air mass will keep windward showers sparse and leeward areas mostly dry. Trades may ease briefly late this week before strengthening again next weekend as high pressure rebuilds to the north. Tropical systems far east of the state will be monitored, but pose no immediate impacts to the islands.

Aviation

Moderate trades will continue through the forecast period. VFR conditions will prevail except isolated MVFR conditions over windward and mauka areas in clouds and showers.

No AIRMETs are in effect and none are anticipated through the forecast period.

Marine

The trade winds will ease tonight as high pressure north of the islands weakens, with the trades then holding at moderate speeds Monday through Tuesday. The trades will restrengthen back to fresh and locally strong speeds Wednesday through Friday as high pressure strengthens north of the island chain.

A south swell is expected to build tonight, then peak around the advisory level late Monday into early Wednesday. A High Surf Advisory will likely be required through this period. As this swell slowly fades during the middle of the week, a new long period south swell will arrive on Thursday, keeping surf elevated through next weekend.

Surf along north-facing shores will remain at flat to tiny levels through next weekend.

Surf along east facing shores will lower slightly Monday through Wednesday as the trades ease upstream of the islands. East shore surf should then build back close to seasonal levels late in the week through next weekend. Additionally, swell from Tropical Storm Elida may give a slight boost to east shore surf during the middle of the week.

Watches, Warnings, Advisories

None.

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