Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 04/16/2026 11:12:00 PM UTC

                        
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FXHW60 PHFO 161312
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
312 AM HST Thu Apr 16 2026

.SYNOPSIS...
A low pressure system lingers far to the north of Hawaii this
morning, supporting continued light and variable winds with
chances for light to moderate showers today. A passing high
pressure system will bring a brief return to easterly trade winds
with subtle drying trends from tonight into Saturday. A series of
low pressure systems passing just north of the state will produce
light to moderate southeasterly winds from Sunday into the middle
of next week along with enhanced shower trends over the western
islands on Monday and Tuesday.

&&

.DISCUSSION...
Looking into the water vapor satellite imagery this morning we
continue to see a divergent Sub Tropical Jet stream over the
Hawaiian Islands producing extensive high level cirrus and middle
level alto-cumulus clouds. These cloudy skies will linger into
early next week with enough instability in the atmosphere to
support brief chances for passing showers each day.

A high pressure system will pass by just north of the state later
tonight into Saturday, briefly building in easterly trade winds
across the region. Wind speeds will become strong enough to limit
sea breezes to terrain sheltered leeward western slopes of each
island. Subtle drying trends will develop during this time period
due to a slight increase in subsidence, downward vertical motions
creating warming and drying effects, making the atmosphere a bit
more stable.

However, the return to easterly trade winds will be fleeting and
vanish quickly by Sunday as a series of low pressure systems
develop and break down the ridge north of the state. These
passing lows appear to track far enough north to limit any heavy
rainfall or flooding issues for the islands. A passing upper level
trough may increase cloud and shower trends over the western
islands of Niihau, Kauai, Oahu and Molokai from Monday through
Tuesday. A weak ridge will settle in over the eastern islands
producing a fairly stable southeasterly wind pattern across the
region. Any additional enhanced showers in this wind driven
pattern will favor southeast slopes of Maui and the Big Island
with modest additional rainfall amounts. Elsewhere rainfall will
be limited as the passing cloud bands will move more parallel to
island mountains and the Big Island will produce a leeside rain
shadow across much of the islands in Maui County.

The long range forecast guidance shows another round of
returning easterly trade winds from next week Thursday into the
following weekend. A building upper level ridge will keep shower
activity to a minimum, with brief passing showers favoring the
typical windward and mountain areas in the overnight to early
morning hours.

&&

.AVIATION...
Southeasterly winds should back more easterly today. Can expect
some windward and mauka SHRA. While MVFR conds can be expected in
SHRA, VFR should prevail.

No AIRMETs in effect.

&&

.MARINE...
A trough lingering to our northwest will maintain gentle to
moderate easterly trade winds through today. The strongest breezes
will occur through the typical windy channels surrounding Maui
and the Big Island. Building high pressure will support moderate
to locally fresh easterly trades across the waters Friday into
Saturday. Winds may briefly reach Small Craft Advisory thresholds
on Saturday. A low pressure system developing to our NW on Sunday
will cause the trades to weaken slightly and veer towards the ESE.
Gentle to moderate ESE winds are expected Sunday into early next
week.

A small, short-period, NNW swell will continue to fade out today.
Small background energy from the west will be possible this
weekend into early next week from Typhoon Sinlaku, but confidence
remains low. A much larger northwest to west-northwest swell is
possible towards the end of next week as Typhoon Sinlaku makes an
extratropical transition early next week.

A small to moderate, medium-period, SSE swell will boost surf along S
shores through Friday then lower over the weekend. Surf along E
shores remains below the seasonal average as trades remain light.
However, increasing trades by week`s end should brings a slight bump
to surf. Low pressure advancing S along the W coast of the US next
week sends a small, medium period NE swell toward the islands by
midweek.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Bohlin
AVIATION...Walsh
MARINE...Kino