Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 04/30/2026 05:39:00 AM UTC

                        
691
FXHW60 PHFO 291939
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
939 AM HST Wed Apr 29 2026

.SYNOPSIS...
Moderate to locally breezy trades will prevail through the next
several days, resulting in periods of shower activity across
windward and mauka locations. An upper-level trough and
developing low will slowly move eastward and become stationary
northeast of the islands, enhancing clouds and shower activity.
By the weekend, the upper-level trough is expected to dislodge
and meander northeastward away from the state, however, periods of
showers are expected to continue.

&&

.SHORT TERM UPDATE...
The forecast remains largely on track this morning, though a few
tweaks were made to shower chances and cloud cover in the short
term based on the latest satellite and radar imagery. The main
updates were to decrease shower coverage across the islands
through midday, while increasing it this afternoon over the Big
Island.

&&

.PREV DISCUSSION...
Issued at 324 AM HST Wed Apr 29 2026

Moderate to locally breezy trades will continue courtesy of the
broad surface high just north of the Hawaiian Islands. Aloft, an
upper-level low and escorting upper-level trough moving eastward
across the Central Pacific will become stationary just northeast
of the islands later today. This will enhance clouds and shower
activity across the state, namely favoring windward slopes of all
islands, with some possible shower activity drifting into leeward
areas briefly. However, by this weekend, the upper-level trough
and associated low will finally dislodge and exit the region,
though periods of showers will likely continue.

Trades will remain the dominant feature through the next several
days, where showers focus across windward and mauka areas, with
only slight variations in the day to day weather pattern across
the state. Model guidance portrays a shallow cold front and
another upper-level trough approaching the islands from the
northwest early next week. Future forecasts will monitor the
evolution of this system as the week progresses and revise as
necessary.

&&

.AVIATION...
Issued at 324 AM HST Wed Apr 29 2026

Moderate easterly trade winds will continue with an upper level
trough producing periods of MVFR conditions in passing showers
mainly over windward mountain areas, and favoring the overnight
to early morning hours. Terrain sheltered leeward areas along the
western island slopes may see afternoon showers as sea breezes
converge with trade winds each day.

No AIRMETs in effect. However, AIRMET Sierra may be needed later
today for mountain obscurations mainly over north and east slopes
of island mountains.

&&

.MARINE...
Issued at 930 AM HST Wed Apr 29 2026

Moderate to fresh east-northeast trades will continue today as a
weak trough shifts to the west and a ridge builds north of the
state. A Small Craft Advisory (SCA) has been issued for the
typical windier waters surrounding Maui County and the Big Island.
The SCA is likely to be extended through at least Friday before a
trough approaches from the northwest this weekend, which will lead
to a period of more relaxed trade winds.

A new northwest to north-northwest (320-330 degree) swell filling in
today should increase surf along north and west facing shores through
Thursday. Looking further ahead, a storm-force low currently in the
North Pacific will send a moderate, longer-period northwest swell
toward the islands for late Friday into Saturday, with above average
surf expected along north and west facing shores. Average H1/10
heights for north facing shores is 6 feet for the month of May
(Goddard-Caldwell Database).

Surf along south-facing shores will remain small through much of
the week, with mainly background south to southwest swell
expected. A small south-southwest pulse should arrive this weekend
from recent activity east of New Zealand, providing an increase in
surf.

Surf along east-facing shores will remain small and choppy
through midweek, with a slight rise possible Thursday and Friday
as trades strengthen.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Thursday for Alenuihaha
Channel-Big Island Leeward Waters-Big Island Southeast Waters-
Maalaea Bay-Pailolo Channel.

&&

$$

SHORT TERM UPDATE...Vaughan
DISCUSSION...Pierce
AVIATION...Bohlin
MARINE...Kino