textproduct: Honolulu

SYNOPSIS

Moderate to locally breezy trade winds are expected through the weekend. An increase in moisture through Wednesday will cause showers to increase over windward and mauka areas. Limited spillover is possible to leeward areas. Drier conditions should arrive late Wednesday and remain through Saturday.

SHORT TERM UPDATE

Showery trade wind weather is expected to continue through tonight and tomorrow morning. This afternoon's sounding showed an elevated inversion height around 9,000 ft associated with the low and mid level trough moving through. This will maintain the possibility of a few heavier showers overnight. Trade winds should also increase a little tomorrow.

PREV DISCUSSION

Issued at 330 PM HST Tue Jun 23 2026 Showers, some briefly heavy, have been moving across most islands in the trades this afternoon. So far, Kauai has been the driest, but moisture is moving west and we expect them to pick up additional showers through the evening and overnight. Winds were averaging 10 to 15 mph, with gusts 20 to 30 mph in the usual spots, through mid-afternoon.

Little change to the forecast this afternoon. Models are consistent in showing a weak upper level low moving from east to west across the area just north of the islands. A weak surface trough is presently moving through the islands, leading to more showers than at this time yesterday. The strongest showers have brief heavy rain. This trough will move off to the west tomorrow.

Trade winds will continue at moderate to occasionally breezy levels through the weekend and into early next week. After the current low level trough and it's associated enhanced moisture move off to the west tomorrow, slightly drier air will move in Wednesday evening through Saturday, leading to a reduction in showers. It won't be dry enough to completely eliminate them, but they will be mainly windward and mauka through the weekend.

AVIATION

Moderate to locally breezy trades expected through the rest of the week. A trough moving up the island chain is causing low cigs and SHRA with IFR/MVFR conds. Conds should improve east to west as the trough moves through.

AIRMET Sierra is in effect for mtn obsc for windward portions of Kauai, Molokai, Lanai and Maui. It is also in effect for the entire islands of Oahu and the Big Island. This may be expanded or augmented through the night as conditions warrant.

While AIRMET Tango is not in effect at this time it is possible as the winds increase tomorrow it may be needed for mod turb downwind of island terrain.

MARINE

Issued at 330 PM HST Tue Jun 23 2026 A low-level trough passing from east to west across the Main Hawaiian Islands tonight will continue to enhance rain shower activity for all coastal and offshore waters. As the trough passes west of the islands tonight, in combination with a strengthening subtropical ridge to the north, trade winds are forecast to increase, prompting the issuance of a Small Craft Advisory (SCA) for the typically windier waters and channels near Maui and the Big Island. Winds will remain moderate to locally strong, which will likely require the SCA to remain in effect through the weekend.

A series of small to moderate, medium to long period south and southeast swells will keep surf along south facing shores elevated through the week. A small, medium period south swell will continue to fade through Wednesday. The forerunners of the next long period south swell will begin to arrive in the islands by Wednesday morning, and then build into Wednesday night, peaking on Thursday with head high to overhead surf heights at most exposed south shore surf breaks.

Surf along east facing shores will gradually build through Wednesday and then hold into the weekend as trade winds strengthen. West facing shores will remain on the small side with a slight south swell wrap. Surf heights along north facing shores experienced a bump today with a bit of north swell energy, though this is forecast to fade tonight returning surf to fairly flat conditions. Another tiny bump in surf is possible Wednesday night into Thursday with a little bit of west-northwest swell energy arriving.

HFO WATCHES/WARNINGS/ADVISORIES

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