textproduct: Honolulu

SYNOPSIS

Trade winds will steadily strengthen through Thursday and a wind advisory has been issued for areas of Maui County and Big Island through Thursday night. Passing showers will continue to move in on breezy to windy trade winds through at least early next week. As usual, these showers will be most frequent during the nights and early morning hours across windward and mauka areas.

UPDATE

No major changes with the forecast this evening. Winds are still on track to steadily increase through Thursday. Wind gusts of around 50 mph have already been measured at select sites downwind of terrain over Maui County and the Big Island this evening. Satellite imagery continues to show passing showers riding in with the strong trade winds focused over windward and mauka areas. A few leeward showers will also be possible tonight.

PREV DISCUSSION

Issued at 337 PM HST Wed May 20 2026 Satellite shows partly to mostly cloudy skies and scattered showers mainly windward and mauka, with isolated showers over South Kona on Big Island. Winds have increased today, averaging 15 to 25 mph with gusts 30 to 40 mph in a few favored locations.

A drier air mass is moving in tonight, and the inversion will lower and strengthen. This will result in gusty winds over and lee side of terrain. Winds are expected to reach advisory thresholds tonight into Thursday for the windier areas around Maui County and the Big Island, where gusts of up to 50 mph will be possible. For Oahu, wind gusts should be slightly weaker but gusts of at least 40 mph should be expected for areas downwind of terrain by late Thursday. Oahu is not currently in the wind advisory as winds are expected to be below advisory thresholds.

For the weekend, windy conditions will likely continue through Saturday. Trade winds should weaken slightly Sunday, but breezy to occasionally strong trades will likely continue into early next week. Trade wind showers will continue to pass through from time to time and will mainly be focused over windward and mauka areas.

AVIATION

Issued at 337 PM HST Wed May 20 2026 Fresh to strong trades will increase tonight and will be locally windy through at least Thursday night as the atmosphere stabilizes. AIRMET Sierra is in effect for mountain obscuration across windward portions of the Big Island, and as a diffuse band of moisture moves through tonight, AIRMET Sierra could be needed over windward slopes elsewhere. AIRMET Tango is in place for low level turbulence over and downwind of terrain. With winds building and stability increasing, this AIRMET will remain in place for at least the next couple of days.

MARINE

Issued at 337 PM HST Wed May 20 2026

The high pressure ridge north of the Hawaiian Islands will strengthen over the next few days, allowing trade wind speeds to increase into the strong to gale range tonight through early Friday morning. A Gale Warning has been issued for the Alenuihaha and Pailolo Channels, and Maalaea Bay starting this evening and the Small Craft Advisory (SCA) has been expanded to all remaining island waters. Expect SCA to continue into the first half of next week.

Small, short- to medium-period north-northwest (330 degree) swell energy will decline through Thursday. The next small north- northwest (330 degree) swell will move into the Hawaii region on Saturday, 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. Meanwhile, strengthening trades will maintain elevated surf along east-facing shores into next week.

HFO WATCHES/WARNINGS/ADVISORIES

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 AM HST Friday 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.