textproduct: Honolulu

SYNOPSIS

Lingering moisture, combined with a departing upper trough, will support periods of locally heavy showers and storms through tonight over the Big Island. Otherwise, trades have returned, and a drier and more stable trade wind pattern is expected through the weekend and into early next week. Showers, mainly windward, will be with us through the period.

SHORT TERM UPDATE

No changes made. Previous forecast remains on track.

PREV DISCUSSION

Issued at 355 PM HST Tue Mar 24 2026

An exiting upper level trough still has cold air aloft, and will keep conditions unstable over the Big Island through tonight. This lead to an extension of the flood watch there through 6 AM HST Wednesday. Windward and high elevation showers have been occurring since late morning, and will continue and strengthen going into tonight. Therefore flash floods are still possible and folks should be prepared the rest of tonight.

For the remaining islands, trades have already built back into the area thanks to a surface high to our north. NE winds averaging 10 to 20 mph with gusts above 30 mph at times were transporting drier air into the region. Windward showers, typical for trade winds, will be with us through the weekend and into next week.

An upper low will swing by to the northeast of the state and push a fairly dry cold front through Thursday night through Saturday night, bringing even drier air to the state. At this time, the forecast is for dewpoints in the mid 50s Saturday night, with upper 50s both Friday and Sunday nights. Looks like a cool weekend is in store.

AVIATION

A persistent convergent low-level cloud band over and upstream of the windward Big Island slopes supports showery conditions continuing into Wednesday. Expect periods of MVFR CIGS/VSBYS in showers moving through, particularly in Hilo, where AIRMET Sierra for mountain obscuration remains in place. Elsewhere, mostly dry and breezy northeast trade wind conditions prevail across the island chain.

AIRMET Tango will remain in effect through Wednesday for low- level turbulence across leeward areas of all islands due to the breezy northeast trades.

MARINE

Issued at 355 PM HST Tue Mar 24 2026

A trough east of the islands will be the focal point for a new weak low to develop tonight. This, combined with high pressure far north of the area, will result in strengthening northeasterly winds across the local nearshore waters tonight. A Small Craft Advisory remains in effect for all coastal waters through Wednesday morning due to these increasing northeasterlies. Winds begin to ease on Wednesday, but favored channels and coastal waters around the Big Island will maintain Small Craft Advisory conditions at least through Wednesday evening. Winds gradually diminish through the rest of the week as the weak low lifts northward away from the islands and the high pressure shifts toward the mainland. A new high pressure develops far northwest of Hawaii late this week, but strengthens and dips south this weekend, leading to trade winds likely strengthening back to small craft criteria into the beginning of next week.

A fading north-northwest swell will be overlapped by a reinforcing pulse of short to medium period north-northeast swell which will peak tonight and then decline Wednesday. The forerunners of another small northwest swell will arrive on Wednesday, with the medium period swell building to a peak on Thursday, before gradually declining through the weekend. For east facing shores, short period energy from rebuilding trades will increase to near seasonal averages tonight and then hold into the weekend. Strengthening northeasterly winds this weekend and potential gales associated with a low around one thousand miles northeast of the islands will lead to the potential for high surf along north and east facing shores by Sunday into early next week.

For south facing shores, small pulses of southerly swell continue to be possible through the rest of the week, which will keep small surf ongoing along south facing shores.

HFO WATCHES/WARNINGS/ADVISORIES

Flood Watch until 6 AM HST Wednesday for Big Island East-Big Island Interior-Big Island North-Big Island South-Big Island Southeast-Kohala-Kona.

Small Craft Advisory until 6 AM HST Wednesday for Kaiwi Channel- Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters-Maui County Windward Waters-Oahu Leeward Waters- Oahu Windward Waters.

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