textproduct: Honolulu

SYNOPSIS

Light to moderate wet trades will continue through Sunday. Winds will increase in speed Monday, becoming moderate to occasionally breezy. Wet trades through Monday night will dry out somewhat Tuesday, and a rather typical trade pattern is forecast to continue from Tuesday into next weekend.

UPDATE

The departing upper level low to the north managed to produce enough deep convection late this afternoon to induce a surface trough nearby. As a result, trades were briefly disrupted over Maui County and portions of the Big Island. As trades began to build back in around sunset, heavy showers developed along windward slopes of Oahu, Maui County, and northern Big Island, and the short term forecast was updated to reflect current conditions. Expect this activity to gradually diminish as the night progresses. The rest of the forecast remains in track.

PREV DISCUSSION

Issued at 338 PM HST Sat May 16 2026 Radar and satellite show numerous showers have been occurring over the state this afternoon, mainly on Oahu and the eastern side of Big Island. Rainfall amounts have ranged from just a few hundredths of an inch up to 3 inches since sunrise today. Winds have been averaging 5 to 15 mph - generally out of the east windward and west leeward.

The upper level low that helped bring so much precipitation to parts of the state yesterday continues to move away to the northeast as it weakens. We still have some instability, but it is significantly lower now. Ridging aloft to our northeast will be slightly weakened by troughing extending off the coast of the southwest mainland, but will still be strong enough to bring the trades back and keep them in place for at least the next week.

Initially, with PW values near 1.5 inches, we will see plenty of trade wind showers. This will change Tuesday when drier air is brought back into the region from the northeast. From Tuesday into at least next weekend, trade showers will be more typical in number and intensity. Wind speeds will generally average 5 to 15 mph Sunday, but increase Monday to 10 to 20 mph, with higher gusts. These moderate to occasionally breezy trades will then persist into next weekend.

AVIATION

An upper level disturbance northeast of the island chain continues to produce unsettled weather conditions with periods of showers and brief MVFR conditions over island mountains this evening. Periods of showers will continue into the early morning hours with decreasing trends on Sunday as the upper level disturbance weakens and drifts farther eastward away from the state.

AIRMET Sierra remains in effect for mountain obscuration for the islands of Kauai, Oahu, Molokai, Lanai, Maui and the Big Island of Hawaii.

MARINE

Issued at 338 PM HST Sat May 16 2026 Winds will remain slightly east southeasterly at moderate to fresh levels through the rest of the weekend. Meanwhile, increasing stability over the region will result in decreasing shower and thunderstorm coverage across the coastal waters. A more typical easterly trade wind pattern will return next week.

A small, medium-period north northwest (320-330 degree) swell will continue to decline through Sunday night, with surf along north- facing shores following suit. A medium-period north northwest reinforcement may provide another small bump in surf along north- facing shores by early morning on Monday, followed by another small reinforcing swell on Tuesday. Surf along west-facing shores will remain mostly steady through the rest of the weekend as the northwest swell influence gradually declines, but a new, long- period south southwest swell fills in.

A mix of small, medium- to long-period south swells will maintain small surf along south-facing shores for the next several days. The long-period south southwest swell described above will increase surf along south-facing shores through Sunday. Additional small, medium to long-period south swell reinforcements will arrive Sunday through mid-week.

Moderate to fresh trades will maintain rough and choppy surf along east-facing shores for the next several days.

Tides will peak around 2.5 to 3.0 ft MLLW this weekend. Minor overwash of low lying coastal areas will be possible during times of high tide.

HFO WATCHES/WARNINGS/ADVISORIES

None.