textproduct: Honolulu

SYNOPSIS

The flooding threat over Big Island has diminished tonight with improving conditions expected through early Friday. Lingering light to occasionally moderate intensity showers will pass across the state through Friday but the majority of this activity will be too light to re-initiate flooding. Trade weather returns this weekend with a frontal passage early next week significantly limiting rain chances while producing a few days of very comfortable, relatively cooler and drier conditions.

UPDATE

Radar currently depicting the heaviest rain falling along Big Island's Hamakua Coast and Hilo regions, between Laupahoehoe and Hilo, this evening. Since this afternoon, many gauges on or near the Hamakua Coast have picked up 3 to near 8 inches of rain. Overall, shower behavior is tapering off but there will still be some cells over Maui County and Big Island that could easily put down a quick half an inch to an inch of rain as they progressively pass to the east. An afternoon ASCAT pass showed that trades are in place across the windward near coastal waters. Weak lower to mid level troughing still resides over the eastern half of the state. A highly moist air mass of well above normal precipitable waters (2.0 to 2.5 inches) within an unstable environment, as evidenced by this afternoon's Big Island thunderstorms, will remain over the state through tomorrow. Thus, tonight and tomorrow's forecast calls for more of the same in terms of widely scattered light to locally moderate intensity shower behavior. Better organized rain clusters, especially interacting with higher terrain, could again tip the bucket to having to issue a Flood Advisory or two for nuisance-type flooding. Mid to upper drier air will begin to work its way into the region this weekend as a result of a passing North Central Pacific trough. So, after another day of overcast and showery weather for many on Friday and the first half of Saturday, the weather will begin to transition to more drier with peeks of clear skies from as early as Saturday evening onward into early Sunday.

PREV DISCUSSION

Issued at 418 PM HST Thu Oct 29 2026

Latest satellite and radar imagery shows isolated thunderstorms over windward Big Island this afternoon. While abundant low-level moisture remains across the state with dewpoints in the 70s, drier mid-level air has moved in over the western half of the state and is shown on the 00Z sounding from Lihue. With the abundant low level moisture still lingering over the western half of the state, any passing showers will be capable of producing brief downpours through Friday. Over the eastern half of the state, the drier mid-level air should be moving in this evening into tonight. Overall, with drier air moving in, and land breezes developing over the Big Island, the current heavy showers and isolated thunderstorms should taper off over the next few hours. So for now, the plan is to keep the Flood Watch going through 6 PM today with no extension anticipated as long as the current bands of heavy rain begin to taper off over the next hour or so.

While the threat of flash flooding should be generally decreasing overnight, some localized heavy rain is still expected over select windward areas of East Maui and windward Big Island tonight through Friday. Mid-level ridging building overhead should keep the threat of any thunderstorms low and should bring stable conditions by Friday afternoon.

For Halloween, weather conditions should generally be fair across the state with gentle to moderate trade winds. Some low level moisture may still linger over the eastern half of the state, which will likely produce some scattered showers over windward and mauka areas. Otherwise, fair weather should prevail for rest of the state.

A strong high building behind a weak front passing near the state, should produce strong northerly trade winds across the state by Sunday evening. Dewpoints should get into the low 60s by Monday, so relatively cool and breezy conditions should be expected on Monday. A breezy to locally strong trade wind pattern is expected early next week with scattered showers focused over windward and mauka areas.

AVIATION

Disorganized -SHRA/SHRA from Maui to the Big Island with trade winds increasing for Kauai to Molokai. Embedded SHRA/+SHRA from eastern Maui to the Big Island with VCTS/-TSRA for the windward Big Island including PHTO. MVFR/VFR common this afternoon and will persist into the evening with brief IFR CIGs/VIS under -TSRA/+SHRA. Overall coverage of SHRA wanes a little overnight with increasing trade winds for tomorrow.

Trade winds from Kauai to Molokai with more variable directions from Maui to the Big Island. Gusty and erratic winds possible around TS on the windward side of the Big Island.

AIRMET Sierra for mountain obscuration remains in effect abv 020 for Oahu, Molokai, Maui, Lanai, and the Big Island through North to East areas. Conditions likely to persist into the evening.

AIRMET Tango for Turbulence remains in effect from Lanai to the Big Island. Moderate turbulence between 100-FL200. AIRMET Zulu is no longer in effect for light icing.

MARINE

Issued at 418 PM HST Thu Oct 29 2026

Weak trough over the central waters will slowly move south and dissipate Friday. This has continued to support showers and isolated thunderstorms over the eastern waters and looks to continue through this evening before conditions slowly improve. Ridging to the north will gradually drive moderate to fresh easterly winds over most waters Friday through the weekend. As trade winds increase, a Small Craft Advisory for the windier waters and channels around Maui County and the Big Island is likely late this weekend into early next week.

The current northwest swell will gradually decline through the evening before a small short period north-northeast swell will fill in Friday and maintain small surf. A larger, long- period northwest swell will arrive late Saturday and will likely push surf above the High Surf Advisory threshold Sunday into Monday. The swell will shift more northerly and may briefly build further on Monday before dropping Tuesday. At the peak of the swell coinciding with the 360 degree direction, a Marine Weather Statement may need to be issued to due the potential for harbor surges at Kahului and Hilo harbor.

Surf along south facing shores will slowly rise through this evening, peak Friday just below High Surf Advisory levels, and gradually decline through the weekend. By early next week, surf looks to remain tiny to small through the forecast period.

Surf along most east-facing shores will remain small and choppy through today but will rise Friday with the wrapping north to north- northeast swell energy, producing periods of moderate surf. Exposed shorelines to the north swell may be impacted along the east side Sunday night into Monday with the potential for surf to reach High Surf Advisory level surf possible.

FIRE WEATHER

Issued at 418 PM HST Thu Oct 29 2026

Due to the recent rain and light wind, fire weather concerns will remain low through Saturday. A front is expected to arrive early next week. Breezy to locally strong north northeast winds and drier conditions are expected in the wake of this boundary passage late Sunday or early Monday. Thus, fire weather concerns will be on the rise through next week.

HFO WATCHES/WARNINGS/ADVISORIES

None.