textproduct: Honolulu

SYNOPSIS

Remnant low Fausto will continue to shift far northwest of the area today. A strong high will build in from the north allowing trade winds to strengthen from east to west across the state today reaching breezy levels by this afternoon and evening. Trades will further strengthen Friday into Saturday under a dry and stable airmass that could produce very windy downsloping winds that may warrant a Wind Advisory. Trades will ease back to the usual breezy levels Sunday into early next week as the high weakens. Typical summertime showers are expected for windward and mountain areas.

SHORT TERM UPDATE

A band of widely scattered light to moderate showers, associated with the remnant of Fausto, is quickly becoming diffused over the Kauai Channel, with the heavier showers well north of Kauai. A hybrid pattern of seabreezes and light to breezy southeast winds could increase chances of clouds and showers over interior and upslope mountain ranges later this morning and early afternoon for the western half of the state. Otherwise, breezy easterly trade winds will push a shallow deck of clouds and with embedded light to moderate showers over the Big Island and Maui County through the morning hours and the rest of the state this afternoon, leading to a more typical summertime trade wind pattern by this evening.

PREV DISCUSSION

Issued at 346 AM HST Thu Jul 30 2026 A band of light to moderate showers will transit through the western half of the state this morning as the remnant circulation and moisture of Fausto exits the area to the west. East to southeast winds can still be expected for Oahu and Kauai for the morning before the typical breezy easterly trade winds fill in during the afternoon. Showers then will focus over the usual windward and mountain areas through the weekend and next week.

Trade winds are then forecast to ramp up Friday and Saturday to strong levels as high pressure to the north strengthens. Model cross sections show the inversion staying around 5,000 ft and mid level temperatures increasing. These factors will increase the chances of strong downsloping winds under an increasingly stable airmass, and could get to wind advisory levels. A wind advisory for parts of the state is being considered and more details will follow as confidence increases. The time period for the strongest winds at this time appears to be Friday night through Saturday afternoon. Dewpoint temperatures are also forecast to decrease as drier air moves in with the strengthening trades. The lower humidity, decrease in showers, and increased winds will elevate the fire weather threat. We will continue to monitor all available guidance and observations.

Sunday into early next week trades will weaken to moderate to locally breezy levels as Hurricane Genevieve tracks far northeast of the state, disrupting the trade wind flow.

AVIATION

Moderate to locally breezy trades will spread from east to west across the island chain today as remnants of tropical cyclone Fausto passes further to the northwest of the state. Meanwhile, an area of enhanced low level moisture will bring clouds and showers to mainly windward portions of Kauai through the morning hours. Some MVFR ceilings and visibility in SHRA may accompany this band as it moves over the Kauai. Trades will remain moderate to locally breezy tonight with showers and clouds favoring windward locations.

No AIRMETs are currently in effect as AIRMET SIERRA has been cancelled early this morning. AIRMET TANGO will likely be issued by this afternoon over and immediate S through W of the eastern islands.

MARINE

Issued at 346 AM HST Thu Jul 30 2026

Variable to light northerly winds will yield to east-southeast to easterly trades building in from east to west across the state today as Fausto's remnant low exits off to the northwest. A Small Craft Advisory (SCA) is in effect through Friday night for strong trade winds throughout the windier waters of Maui County and the Big Island. Trades strengthen through the weekend, which could necessitate an expansion of the SCA to the rest of the coastal waters later on. A weakness in the ridge of high pressure develops on Sunday, which will cause trade winds to weaken again for early next week.

A medium period south swell peaking today will bring south shore surf around the summer average (5-6ft). Surf then fades gradually through the weekend while a mix of small south swells maintains surf slightly below the seasonal average.

Surf along east shores will trend up tonight into the weekend due to a combination of building short period trade wind swell and renewed medium to long period east swell emanating from Hurricane Genevieve in the East Pacific. North shores will see flat to tiny surf through early next week as a weakening Post-Tropical Cyclone Fausto moves away from the islands and no significant north swells are forecast.

FIRE WEATHER

Issued at 346 AM HST Thu Jul 30 2026

Trade winds are expected to strengthen from east to west across the state Thursday becoming breezy to locally strong Friday into Saturday. As the winds become strong late Friday into Saturday, a drier more stable airmass will filter in, increasing the potential for locally strong downsloping winds. While KBDI will remain below the critical thresholds there could still be some fire weather concerns.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory until 6 AM HST Saturday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.