Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 04/02/2026 11:59:00 AM UTC

                        
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FXHW60 PHFO 020159
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
359 PM HST Wed Apr 1 2026

.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.


&&

$$

DISCUSSION...Blood
AVIATION...Evans
MARINE...Foster