textproduct: Honolulu

SYNOPSIS

A light land and sea breeze pattern will produce afternoon clouds and spotty showers over land and partial clearing at night. Trade winds will redevelop late Wednesday and strengthen Thursday and Friday focusing rainfall over windward and mauka areas.

SHORT TERM UPDATE

The forecast is on track and no updates to the forecast are anticipated tonight. The afternoon showers that formed over the interior and Koolau range on Oahu fizzled out shortly after sunset as anticipated. Expecting limited shower activity overnight.

PREV DISCUSSION

Issued at 321 PM HST Tue Apr 21 2026

A humid land and sea breeze regime will prevail over the next 24 hours or so. Isolated showers near the coasts will dissipate during the early morning, followed by interior clouds and spotty showers in the afternoon. While stability is slowly returning, a briefly heavy shower is still possible in the afternoon and evening.

Trades will slowly redevelop on Wednesday as the low to the north drifts east and weakens. The combination of the building trades and gradually increasing stability will lessen chances for afternoon showers. Trade winds will strengthen Thursday and Friday and will persist into early next week as surface high pressure becomes established north of the islands. The moderate to locally breezy trades and more stable conditions will push dew points back into the lower 60s, providing relief from the recent humidity. Showers will become focused over windward slopes.

AVIATION

Land breezes will clear out clouds and showers tonight, bringing mostly clear conditions to the airports. Tomorrow morning and afternoon will see sea breezes and associated cloud and shower buildups over interior areas before northeasterly trade winds fill in by the evening. Once the trade winds return, showers will return to focusing over windward and mountain areas. VFR conditions will prevail with brief MVFR conditions any in showers

No AIRMETs in effect.

MARINE

Issued at 321 PM HST Tue Apr 21 2026

A weak low north of the area will continue to drift eastward and further away from the state over the next few days. As the low drifts further east, a ridge of high pressure will fill in north of the state, which should bring the return of moderate trade winds by Wednesday evening. Light winds during the night tonight and day time Wednesday will lead to land and sea breeze development near the coastlines. By Thursday evening, we should see moderate to fresh trade winds and by the weekend, we could see moderate to locally strong trade winds as another high builds north of the state.

A small, medium-period, west-northwest to northwest (300-330) swell continues to fill in this afternoon and will likely peak tonight, then gradually decline over the next few days. Another smaller reinforcing swell will also fill in tonight into Wednesday.

A moderate, medium-period north-northeast swell also started filling in today and will likely peak on Wednesday near advisory thresholds for east facing shores. This swell will produce above average surf for select north and east facing shores on Wednesday, before slowly declining through the end of the week. Strengthening trades late this week will support closer to seasonal average surf for east facing shores into the weekend.

As the former Super Typhoon Sinlaku made its extra tropical transition last weekend, it gradually traveled eastward along our great circle route. Although the former typhoon was relatively compact, altimeter did show some higher seas of 14 to 18 feet far west of the state a few days ago. This could bring some west swell along select exposures starting today through the next several days. Peak energy from the former Typhoon is expected Wednesday or Thursday and could wrap into select southwest facing exposures. Otherwise a small southwest swell from the Tasman Sea should arrive this weekend.

HFO WATCHES/WARNINGS/ADVISORIES

None.