Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 04/26/2026 11:37:00 PM UTC

                        
798
FXHW60 PHFO 261337
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
337 AM HST Sun Apr 26 2026

.SYNOPSIS...
A high pressure system far north of the Hawaiian Islands will
slowly drift east over the next two days, however a broad ridge
north of the region will remain in place keeping easterly trade
winds in the forecast through the end of next week. A low level
trough moving across the region today and an upper level trough
approaching the islands on Monday will deepen into an upper low
by Tuesday, leading to increasing cloud and shower trends across
the region lasting into the end of next week. Shower activity
during this time period will favor windward mountain areas in the
overnight to early morning hours with brief periods of showers
drifting into leeward areas.

&&

.DISCUSSION...
Satellite imagery this morning shows a low level trough drifting
westward through the islands on the easterly trade winds today
enhancing clouds and showers across the state. The highest
coverage for clouds and showers will develop along the
eastern mountain slopes of each island as trade winds lift the
cloud bands over mountain ridges enhancing rainfall activity. An
upper level trough farther to the northwest of the islands
continues to track towards the state. Expect wind speeds to pick
up this afternoon over the eastern islands and then later tonight
over the western islands as the surface trough continues to drift
westward and higher pressure builds in.

By Monday and Tuesday an upper level trough will approach the
Hawaiian Islands from the northwest direction. Models are in good
agreement that this upper trough will deepen into a closed low on
Tuesday near Kauai. Expect temperature inversion heights to rise
from 6,000 to 8,000 feet elevation, deepening cloud heights,
producing a wet trade wind weather pattern across the state.

This upper low will slowly drift eastward across the region on
Tuesday with a troughing pattern lingering just northeast of the
state into Friday. The upper low`s upstream position will lift
the clouds to higher heights just east of the island chain,
producing continued wet trade wind weather favoring windward
island mountain slopes, especially in the overnight to early
morning hours. The long range rainfall forecast grids were
adjusted higher to account for these increasingly unsettled
weather trends.

&&

.AVIATION...
Moderate to locally breezy trades through early next week. Low
cigs and SHRA may occur over windward sites, bringing brief MVFR
conditions, however broadly VFR conditions are expected through
the period.

No AIRMETs in effect. Low-level turb is possible should trade
winds strengthen, however conditions are not expected to warrant a
turb AIRMET at this time.

&&

.MARINE...
The easterly trades have eased slightly compared to the past
couple of days as a weak surface trough moves through the region
from east to west. Guidance indicates trades will strengthen back
to fresh to locally strong levels tonight into early this week
once this feature shifts west of the area. This will likely
support a return of Small Craft Advisory conditions across the
typically windier waters surrounding Maui County and the Big
Island. Strong high pressure rebuilding far north of the state by
midweek should maintain strong trades, with advisory-level winds
potentially expanding to additional coastal waters statewide.

Surf along north facing shores will peak today near the late-
April seasonal average, then gradually ease through the first
half of the week. Offshore and nearshore buoy observations
support this trend, showing a decent medium-period pulse moving
through early this morning. An upward trend is expected during
the second half of the week as swell generated by a broad low
lifting north into the Bering Sea near the Date Line reaches the
islands. Looking farther ahead, confidence remains lower due to
model differences, but some guidance continues to suggest a more
potent storm could develop over the far northwest Pacific Monday
into Tuesday. If this scenario materializes, a longer-period
northwest swell could arrive by next weekend, with surf heights
potentially approaching advisory levels along exposed north and
west facing shores.

Surf along south facing shores will trend up, though likely
remain somewhat inconsistent, as a southwest swell arrives and
peaks over the next 24 hours. This will be followed by a gradual
downward trend by Monday. Another small south-southwest pulse may
arrive next weekend from activity within our swell window east of
New Zealand.

Surf along east facing shores will remain relatively small and
choppy due to a combination of locally wind-driven seas and a
small northeast groundswell moving through today.

&&

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

&&

$$

DISCUSSION...Bohlin
AVIATION...Evans
MARINE...Gibbs