textproduct: Honolulu

SYNOPSIS

A broad ridge north of the Hawaiian Islands will dominate our weather into Saturday, with moderate to locally strong easterly trade winds. An upper level trough near the islands will help to enhance some of the trade winds showers.

PREV DISCUSSION

The forecast has been updated to follow the latest National Blend of Models for PoPs and related fields. Overall little change in the forecast. The winds have been tweaked to reflect a slightly higher trend than before, based on the high resolution model guidance.

Satellite shows some showery clouds riding in on the trade wind flow. A ridge far north of the islands will remain in place into the middle of the week, with the pressure gradient over the islands steady. As such, the winds have been tweaked to reflect a slightly higher trend as seen in a number of the high resolution models. Some of the high resolution guidance would suggest advisory level winds reaching some of the windier areas at times, but do not feel this is representative of overall conditions in the next couple of days.

The overnight 12Z sounding from Hilo showed a strong temperature inversion around 9,000 feet, up from 6,000 feet the previous night. Technical issues preventing a sounding from Lihue both yesterday afternoon and last night.

High pressure at the surface will linger through the week, with some weakening of the pressure gradient over the islands during the second half of the week. An upper level low forming to the west of the islands in the next 24 hours could help to enhance trade wind showers as it moves closer to the islands at the end of the week. At this time, the global model thunderstorm probabilities are not impressive. Additionally, near normal 500 and 700 mb temperatures are expected in the global models. The GFS brings in higher precipitable water than the ECMWF near Maui County and the Big Island for the upcoming weekend. At this time it would seem the upper low/trough could enhance trade winds, but not expecting much beyond that based on the current model runs.

AVIATION

Moderate to breezy trades will continue for the next few days. Low cigs and SHRA possible over windward and mauka locations. MVFR conds possible in SHRA, otherwise VFR prevails.

AIRMET Sierra remains in effect for mtn obsc for windward locations of the Big Island.

AIRMET Tango also remains in effect for mod low-level turb over and downwind of terrain across all islands.

MARINE

Issued at 323 AM HST Mon May 25 2026 Fresh to strong easterly trades will persist through the first half of the week as the ridge remains north of the state. This will allow the Small Craft Advisory to continue, particularly across exposed waters and channels. Expect a gradual downward trend through the second half of the week and next weekend due to a weakness forming in the ridge as a front passes far to the north.

Surf along south facing shores will gradually lower today as a medium-period south swell lingers. A fresh long-period south swell will arrive Tuesday, then build to near the seasonal average through midweek before slowly easing Thursday. A more significant long-period south-southwest swell is expected by next weekend due to a storm-force low that passed southeast of New Zealand over the weekend. Satellite data showed a large fetch of 40 to 50 kt winds generating seas of 35 to just over 40 ft, focused toward Hawaii along the 190-degree directional band. Expect surf to begin building locally Friday with 20+ second forerunners, then peak above/around the advisory level over the weekend. For the long range, expect a similar trend to persist through the first week of June as the active pattern persists within our swell window down around New Zealand.

Surf along exposed north and west facing shores will lower today as a small north-northwest swell lingers, but will trend up once again on Tuesday as the late season North Pacific activity continues. Although the bulk of the energy from this next swell will be focused northeast of the islands, expect long-period forerunners to arrive Tuesday, with this source gradually building down the island chain thereafter. Above-average surf is likely by daybreak Wednesday near the peak before lowering Thursday.

Surf along east facing shores will remain rough through midweek, then gradually lower later in the week as the trades ease.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory until 6 PM HST this evening for Big Island Windward Waters-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters-Maui County Leeward Waters-Oahu Windward Waters.

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