Swell Matrix

Area Forecast Discussion

National Weather Service Honolulu Hi

829 pm hst Sun jul 12 2026

Synopsis

Moderate to locally breezy trade winds will persist through Monday as high pressure remains north of the state, with weaker trades Tuesday through at least Friday. Windward and mauka showers will continue, with a slight uptick in moisture likely Tuesday into Tuesday night, and possibly from Friday into next weekend.

Aviation

Breezy trade winds will continue, bringing intermittent shower activity across the islands through the period. Intermittent MVFR is possible under showers, otherwise VFR is generally expected.

AIRMET Sierra is in effect for windward Kauai. This is expected to remain in effect through the overnight hours, and may potentially expand to other islands depending on how shower activity develops overnight.

AIRMET Tango also remains in effect for low-level turbulence downwind of terrain, and is expected to continue for the next several days as we remain under a breezy trade wind pattern.

Marine

Strong high pressure north of the islands will keep fresh to strong trades blowing tonight, before easing Monday through Tuesday as the high lifts northeast and weakens. A Small Craft Advisory (SCA) is in effect for all waters through 6 PM Monday. The SCA may be scaled back some on Monday, further reduced in areal coverage on Monday night, and will likely not be needed for any waters by Tuesday. The lighter trades should continue through Wednesday night, then may increase a bit Thursday and Friday as high pressure northeast of the islands drops a bit further south and tightens up the local pressure gradient.

A small, long-period southwest swell will continue to fill in tonight, peak on Monday, then gradually decline through the middle of the week. Surf along east-facing shores will remain rough and choppy through Monday, then steadily decline through the middle of the week. A series of overlapping small south and southwest swells will then give a small boost to the surf along south facing shores Thursday through next weekend, with perhaps a more sizable south swell moving in early next week.

A series of small, low to medium period west to west-northwest swells generated by former Super Typhoon Bavi will be possible throughout the week. Otherwise, no significant north or northwest swells are expected, so surf along north-facing shores is expected to remain flat to tiny.

Peak monthly high tides combined with water levels that are running slightly higher than predicted will lead to minor flooding along the shoreline and in low-lying coastal areas. Coastal flooding is possible around the daily peak tide, which will be during the afternoon hours. A Coastal Flood Statement remains in effect through Tuesday afternoon.

Watches, Warnings, Advisories

Small Craft Advisory until 6 PM HST Monday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters- Maalaea Bay-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters-Pailolo Channel.

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