textproduct: Honolulu

SYNOPSIS

The flooding threat will continue through tonight as a surface trough shifts over the eastern half of the state in the midst of deep tropical moisture and modest instability. Conditions are expected to improve heading into Thursday, with moderate trade winds returning this weekend.

SHORT TERM UPDATE

The trough axis has shifted eastward across Maui County this morning. Moderate to heavy showers with isolated thunderstorms will continue along this boundary through tonight, with lighter showers expected over the western end of the state that will become more focused over windward and mauka areas as moderate trades fill in. However, short term model guidance points to another round of heavy rain moving over Maui County and possibly Oahu this afternoon.

While the threat of heavy rain continues overnight, it's expected to taper off heading into Thursday as the atmosphere gradually stabilizes. So even while scattered to numerous showers are expected to continue as plentiful moisture remains over the state along with weak surface convergence near the trough boundary, which is expected to stall between Maui and the Big Island, rain rates should be manageable. As such, the Flood Watch will likely not be extended.

In addition, the High Wind Warning for the Big Island summits has been cancelled as winds have fallen below criteria this morning.

PREV DISCUSSION

Issued at 325 AM HST Wed Oct 28 2026

Showers and a few isolated thunderstorms are ongoing across the state this morning. The bulk of the rain has stayed over the central portions of the state with heavier rain moving towards Molokai, Lanai and Maui. Total rainfall that has fallen ranges from a half inch to 2 inches over portions of Oahu. Slow moving cells may become anchored along the terrain of the islands, which could lead to flash flooding anywhere. The High Wind Warning for the Big Island summits continues through noon. The Flood Watch will also continue and the possibility of extending it will be evaluated today. A few thunderstorms with localized damaging gusty winds may develop along the trough.

The threat of heavy rainfall will diminish Thursday and Friday. The jet stream aloft will lift to the north as the upper level trough moves to the west and an upper level low develops along the trough. The weak surface trough, with ample moisture will likely linger, providing a chance for spotty heavy showers.

Friday night into Saturday a brief period of trade winds may return as the lingering moisture associated with the trough is pushed south of the islands. The GFS and ECMWF are showing breezy northeast winds developing Sunday as a shallow front moves near or over the state.

AVIATION

Disorganized -SHRA with embedded +SHRA primarily from Lanai and Molokai SE to the Big Island. While VCTS/TS is not included in TAFs, we cannot rule out an isolated storm this afternoon and evening, generally Oahu to the Big Island. MVFR with periods of IFR CIGS/VIS expected into this evening, especially with +SHRA. Improving VIS/CIGS from NW to SE generally after 29/06Z to more of a VCSH/-SHRA. Kauai will remain NW of the activity with VCSH and usual trade wind flow.

Surface winds remain generally weak. However, thunderstorms could bring brief gusty and erratic winds.

AIRMET Sierra for mountain obscuration remains in effect abv 020 for Oahu through the big Island due to the the widespread low clouds and pockets of moderate to heavy rain showers.

AIRMET Zulu is in effect for light ice from Oahu to the Big Island in layer 140-FL200 with conditions expected beyond 29/22Z.

MARINE

A surface trough stretches across Maui County waters this morning, and a broad weakening surface low centered roughly 950 nm northeast of the state is keeping the local pressure gradient somewhat weak. As a result, moderate easterly will prevail north of the trough with lighter southerly winds to the south of the trough, and the Small Craft Advisory has been cancelled. However, locally fresh winds are expected near the trough today, and isolated thunderstorms could produce erratic localized wind gusts over gale force. The trough and possible low will weaken near the Big Island Thursday, allowing building ridging to the north to drive moderate to fresh easterly winds over most waters and southerly winds near Big Island. The trough will move south of Big Island Friday, and moderate to locally fresh trades will prevail Friday night into the weekend. Stronger northeast winds may develop late Sunday and Monday and require an SCA.

A small northwest swell will continue a slow decline through Thursday then fade on Friday, but a small, short-period north- northwest swell will maintain small surf along northern shores during the next several days. A larger, long-period northwest swell will arrive late Saturday and may push surf above the high surf advisory threshold Sunday. The swell will shift more northerly and may briefly build further on Monday before dropping Tuesday.

A series of overlapping south-southwest swells will continue through the weekend. The current swell is expected to produce surf above seasonal averages today, with an additional pulse late Thursday maintaining above average surf into Friday. Surf along south-facing shores will decline gradually this weekend into early next week.

Surf along most east-facing shores will be dominated by wrapping north to north-northeast energy that could produce periods of moderate surf. Strong northeast winds and a large, rough north- northeast swell are possible Sunday night and Monday.

FIRE WEATHER

Issued at 325 AM HST Wed Oct 28 2026

Deep tropical moisture over the islands is bringing at times heavy rain and a few thunderstorms and is expected to last through tonight and possibly into Thursday. Fire weather concerns will be low through the next several days.

HFO WATCHES/WARNINGS/ADVISORIES

Flood Watch through late tonight for for all Hawaii islands.