textproduct: Honolulu

SYNOPSIS

Partly cloudy skies with lower humidity under breezy trades will continue the next several days. Limited shower activity will be confined to primarily windward zones and mauka slopes. Long range model guidance are coming more in line with the evolution of a deepening trough northwest of the state mid next week. This trough will pull up a more mositure-rich southern air mass and likely be the impetus to higher statewide precipitation.

DISCUSSION

Issued at 359 PM HST Wed Apr 1 2026

Another pleasant day here in the islands with mostly sunny skies along many coastal areas and surrounding nearshore waters as cumulus build up along warmed mauka slopes. Morning ASCAT passes clipped the western half of the state and have verified that trades over these western waters are fading a touch. Moderate to fresh winds across such trade exposed areas as Kaena Point in northwest Oahu, Kalaupapa on Molokai and Big Island's North Kohala district are a clue that winds have stayed up through the island channels, especially around Maui County and Big Island. Afternoon near coastal observations and high resolution modeling are maintaining these amped up channel winds through Thursday, strongest over Ma'alaea Bay and the Pailolo and Alenuihaha Channels where winds should remain at Small Craft Advisory criteria. Overall trades will fade a bit Friday and this weekend as the pressure gradient relaxes in response to weak surface high moving onto the U.S. mainland's west coast.

Upper ridging nosing in from the west will guarantee a few more of these pleasant days for the majority of the Aloha State. Partially cloudy skies and continued dry conditions, with upper 50 to middle 60 F dew points, will be the rule. Afternoons will warm into the average middle to upper 70s along and near the coast, into the 60s above 2-3 kft. Tonight's full moon will clearly be seen in frequent lunar peeks between the passing low level clouds. Evening breezy coastal trades over windward areas while land breezes take hold within wind-sheltered interiors allowing temperatures to cool back into the middle 60s to low 70s. Local soundings depict a moistened lower 6-7 kft boundary layer capped by bone dry mid to upper layer air. This resident stable, dry air mass will guarantee any short-lived precipitation will be very light. Quick passing light showers will primarily focus along eastern-facing upslope mauka and within higher elevations with the occasional offshore shower passing across windward coastal areas.

The next significant weather producer for Hawaii will be in the form of a deepening trough west northwest of the islands early next week. Ridging passing north of the state this weekend will leave a wake for which a trough will begin to take shape next Monday. There will be a couple of shortwave disturbances that will travel into this trough, further deepening it as its axis nears the northwest offshore waters by late Wednesday into Thursday. The development of this trough will veer our regional winds more south of east. Higher humidity over more southern latitudes will be drawn northward and over the state through mid to late week. There should be just enough instability and lift provided by a negatively-tilted vicinity trough, along with split jet diffulence, within an near maxed out precipitable water air mass (for early April) to initiate statewide rainfall Wednesday and Thursday. At this time a week out, the main hazard is forecast to be locally heavy rain that, if it occurs, could result in flooding. In placing this next weather event in perspective is the GFS ensemble 'worse case scenario' (90th percentile probability) of Wednesday through Friday's average storm total QPF (Quantity of Precipitation Forecast) is between 2 to 4 inches. The big question mark going into next week will be on the timing and intensity of this mid to late week rain.

AVIATION

Issued at 359 PM HST Wed Apr 1 2026

Moderate to locally breezy ENE trade winds are expected today, before gradually weakening through the rest of the week. Embedded isolated and brief showers continue to primarily impact windward and mountain areas. MVFR conditions are possible within showers while VFR prevails elsewhere.

AIRMET Tango is in effect for moderate turbulence over most of the islands between FL250 and FL350. This area of turbulence is expected to weaken by the evening tonight.

MARINE

Issued at 359 PM HST Wed Apr 1 2026

High pressure north of Hawaii will shift eastward and weaken over the next couple of days, causing trade winds to diminish. A Small Craft Advisory is in effect for the typically windier waters around Maui County and the Big Island through Thursday night.

Moderate north and east-facing shore surf continues to be generated by a short period northeast (040 degree) swell which will gradually diminish tonight and Thursday. Breezy winds will also bring rough conditions to east facing shores through Thursday, but will decline through the rest of the week.

The next small, medium-period northwest (310 degree) swell will arrive this weekend to bring a small bump in surf for north and west facing shores. Along south facing shores, expect small reinforcements to sustain small surf through the week.

HFO WATCHES/WARNINGS/ADVISORIES

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