textproduct: Honolulu

SYNOPSIS

A high pressure system drifting slowly from west to east far north of the Hawaiian Islands over the next few days will increase easterly trade winds into the moderate to breezy range lasting into the middle of next week. Brief pulses of enhanced showers are forecast with three passing easterly waves favoring the windward mountain areas in the overnight to early morning hours starting Friday night and lingering into Tuesday morning.

SHORT TERM UPDATE

A high pressure system drifting slowly from west to east far north of the Hawaiian Islands over the next few days will increase easterly trade winds into the moderate to breezy range lasting into the middle of next week.

Three low level easterly waves will ride into the islands on the strengthening trade winds bringing pulses of higher shower coverage favoring Friday night, then late Saturday, and the last one unfolding from Sunday through Monday. The last of these easterly short wave troughs might be the strongest of the three with pulses of showers extending over the typically drier leeward areas at times. Forecasting rainfall amounts with these waves is always challenging due to variations in arrival timing and their intensity relative to each island.

Overall the afternoon forecast grids look reasonable. No evening updates.

PREVIOUS DISCUSSION

Issued at 359 PM HST Wed Oct 14 2026 Radar and satellite show scattered showers and mostly cloudy skies across the Puna and Ka'u districts of the Big Island this afternoon. Skies were partly to mostly sunny with isolated showers over eastern Maui, and mostly sunny elsewhere. Winds were generally out of the east to northeast at 5 to 15 mph, except for locations downwind of terrain, where light west winds were common.

Forecast models are in good agreement that a series of surface high pressure systems will move west-to-east across the northern Pacific, giving us an extended period of trade winds. By early next week, surface troughing may develop as a strong upper level ridge develops to our north. This troughing could lead to an increase in showers from late in the weekend into early next week, especially on the eastern end of the state. Confidence is not high at this time, as models are not in agreement on how much moisture may move into the region. Otherwise, expect a typical trade wind regime, with mainly windward and mauka showers, most numerous at night.

AVIATION

Moderate trades will strengthen to breezy levels Thursday as a ridge builds north of the islands. An area of moisture moving east to west across the state will bring clouds and showers to the windward and mauka areas. Brief MVFR ceilings may occur within better organized showers, but mostly VFR conditions should prevail.

AIRMET Sierra has been issued for windward areas of the Big Island as the above mentioned area of clouds and showers move in. Maui may need to added overnight as the clouds and showers spread to this AIRMET later this evening.

MARINE

Surface high pressure far northwest of the islands will move closer tonight and Thursday, then build as it moves to the north then northeast of Hawaii on Friday. As a result, trade winds will gradually increase to fresh to locally strong levels over the next couple of days. A Small Craft Advisory (SCA) has been issued for the typically windy waters around Big Island and Maui starting Thursday. A stronger surface high will pass far north of the islands late Saturday and Sunday, likely increasing trade winds and possibly necessitating an expansion of the SCA to additional waters. Elevated trade winds will persist into early next week.

The current northwest swell will continue a gradual decline through Thursday, followed by a moderate north-northwest swell Friday through the weekend. The current swell has lowered to around 4 ft at 12 seconds this evening and will slowly fall through Thursday. The next swell will be from the north-northwest and will arrive Friday. Surf along north and west facing shores should top out around seasonal average during the peak of the swell Friday afternoon and Saturday, then slowly decline late Saturday and Sunday as the dropping swell shifts more northerly and a smaller overlapping northwest swell arrives. Both swells will fade early next week.

Surf along south facing shores will briefly fall near or just below seasonal average as the current south swell continues a slow decline tonight. A new long-periond south swell will build Thursday and may push south shore surf back above seasonal average through Friday. The swell will slowly decline Saturday through early next week.

Surf along east facing shores will remain small through Thursday and will steadily increase Friday as trade winds strengthen over the region. Rough trade wind swell will produce east shore surf above seasonal average Saturday through early next week.

FIRE WEATHER

Issued at 359 PM HST Wed Oct 14 2026 Moderate trade winds will strengthen to breezy levels Thursday. Dry air will keep RH levels at near-critical values each afternoon for parts of the state Friday through Sunday. RH values are expected to increase from Monday through the middle of next week. Winds will remain below critical thresholds. Inversion heights today should range from about 5,000 to 6,000 ft through Thursday.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory from 6 AM Thursday to 6 PM HST Saturday for the typical windier waters and channels near Maui and the Big Island.