textproduct: Honolulu

SYNOPSIS

Breezy to locally windy trades will weaken slightly Friday into Monday and will then hold at moderate strengthen through the remainder of the week. Showers will favor windward and mauka areas, with little rainfall over most leeward sections.

SHORT TERM UPDATE

No changes to the forecast this evening with the forecast on track. Winds have decreased this evening in the diurnal trend. Will continue to monitor winds overnight to make final decisions on the Wind Advisory that is in effect overnight.

PREV DISCUSSION

Issued at 331 PM HST Thu May 21 2026 Locally windy trades are in place this afternoon and should persist tonight. A robust 1034 mb surface high centered about 1,000 miles north of the islands is driving the strong trade wind flow, and little change is expected overnight. Meanwhile, mid level ridging will continue to produce stable conditions and cause the trades to become accelerated over and downwind of prominent terrain. As a result, a Wind Advisory remains in place for portions of Maui County and Big Island through tonight. Even though the atmosphere is stable and precipitable water is near to below seasonal average, showers have been somewhat active over some windward areas, especially on Big Island. Expect the trades to continue to focus rainfall over windward and mauka areas, as well as over the Kona slopes of the Big Island each afternoon. Other leeward sections should see little rainfall.

Modest changes are expected on Friday. The surface high will start to slowly weaken, leading to borderline Wind Advisory conditions. Given uncertainty, we will leave it to the night shift to decide whether or not to extend the advisory, which currently expires at 6 AM. Little change in the the rainfall pattern is expected, with showers generally light to moderate and focused windward.

Trades will drop a notch during the weekend but will still remain breezy through the Memorial Day holiday. The surface high driving the winds will weaken slightly but remain at around 1029 mb, strong enough to produce breezy trades. Stable conditions will continue, and modest windward rainfall and a few afternoon showers over the Kona slopes are expected. Moderate trade winds will prevail Tuesday through the middle of next week.

AVIATION

Elevated trades will continue across most sites this evening into tomorrow, however some weakening is expected heading into the weekend. Broadly expecting VFR conditions across most sites, however windward sites may see intermittent shower activity overnight, leading to localized MVFR and even IFR conditions at times.

AIRMET Sierra is in effect for mountain obscuration across windward Big Island, with conditions expected to improve by late Friday morning.

AIRMET Tango remains in effect for all islands due to low level turbulence over and downwind of terrain, which is expected to remain in place so long as trade winds continue to be amplified.

MARINE

Issued at 331 PM HST Thu May 21 2026 The strong high pressure ridge north of the Hawaiian Islands will maintain easterly trade winds in the strong to gale range through Friday morning. A Gale Warning remains in effect for the Alenuihaha and Pailolo Channels, and Maalaea Bay. The Gale Warning may need to be extended through the day Friday as there does not seem to be much change in the strength of the high pressure. The Small Craft Advisory (SCA) for all remaining island waters has been extended through the day Saturday. Expect SCA to continue into the first half of next week for all or portions of the state.

A high surf advisory (HSA) remains in effect for all east facing shores through Friday afternoon due to strong trade wind swell holding into the weekend. Winds may ease a touch tonight allowing surf to drop below advisory levels Friday afternoon through the weekend but conditions will remain borderline and thus will continue to monitor in case there is a need to extend the HSA.

Surf along north facing shores will remain small into Friday. The next small north- northwest (330 degree) swell will move into the Hawaii region Friday afternoon, gradually increasing surf heights along north and west- facing shores through the weekend.

A series of small, long-period south swells will support near- average surf along south-facing shores over the next several days.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Advisory until 6 PM HST Friday for Big Island East-Big Island North-Big Island Southeast-East Honolulu-Kahoolawe-Kauai East-Kauai North-Kipahulu-Koolau Windward-Maui Windward West- Molokai Southeast-Molokai Windward-Olomana-South Haleakala- Windward Haleakala.

Wind Advisory until 6 AM HST Friday for Big Island North-Big Island South-Big Island Southeast-Kahoolawe-Kohala-Lanai Leeward- Lanai Mauka-Lanai South-Lanai Windward-Maui Central Valley North- Maui Central Valley South-Maui Leeward West-Maui Windward West- Molokai Leeward South-Molokai North-Molokai Southeast-Molokai West-Molokai Windward-South Haleakala.

Small Craft Advisory until 6 PM HST Saturday for Big Island Leeward Waters-Big Island Southeast Waters-Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters.

Gale Warning until 6 AM HST Friday for Alenuihaha Channel- Maalaea Bay-Pailolo Channel.