567 
FXHW60 PHFO 060719
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
919 PM HST Sun Oct 5 2025

.UPDATE...
Marine Section has been updated to better show current trends.

&&

.SYNOPSIS...
A surface trough approach and then move over the western end of
the state tonight through Monday. As this occurs, winds will 
weaken and become more southeasterly, resulting in a daytime sea 
breeze and nighttime land breeze regime. As the feature moves
through, increased clouds and showers are expected over the
western islands through at least Monday. Moderate trade winds 
will return near the end of the week.

&&

.DISCUSSION...
Regional satellite imagery shows a well-defined band of showers 
associated with a trough north of the main Hawaiian Islands, just 
inside the northern offshore waters this afternoon. In addition to
this surface trough, a distinct upper-low is located near 30N 
150W as of 0100 UTC, where towering cumulus and heavier showers 
are observed roughly 550 to 800 miles northeast of Honolulu. 
Closer to the islands, a late morning ASCAT pass and surface 
observations from around the state throughout the day reveal 
moderate trade winds that are slightly more northeasterly over the
western end of the state in closer proximity to the surface 
trough, and more easterly over the eastern end of the state 
farther away from the feature. Relatively few showers and low 
clouds are moving into the islands on the moderate trades at this
time, though afternoon sea-breeze induced cloud buildups and a 
few showers have developed over the Big Island again today.

As strong high pressure builds behind a cold front moving quickly
eastward across the North Pacific well north of the region, the 
surface trough near the main Hawaiian Islands will be displaced
southward near and then over western islands. The band of clouds 
and showers discussed earlier associated with this feature is 
expected to approach Kauai tonight, reaching and passing over the 
Garden Isle Monday morning. As it weakens, it could also reach 
Oahu by the early afternoon hours on Monday. With this afternoon's
forecast updates, shower chances have been adjusted upward for 
the western end of the state through Monday, though it is notable 
that neither the HREF (High Resolution Ensemble Forecast System) 
probabilities nor the NBM PQPF (Probabilistic Quantitative 
Precipitation Forecasts) get too carried away with rainfall 
accumulations, likely due to the band's quick movement over the 
islands and weakening nature. 

As the trough approaches the western islands, the background 
moderate trade wind flow will weaken to become light out ahead of
it. This will mark a return of daytime sea breezes and overnight 
land breezes, particularly for the eastern islands on Monday, then
statewide from Monday night through at least Wednesday night as
the light background winds become more southeasterly. With this 
pattern, increased leeward and interior shower activity can be
expected from late morning through early evening each day,
followed by clearing and limited showers each night.

Moderate trades may begin to fill back into the region by Thursday
or Friday as strong high pressure builds far to the northeast of
the region and then moves southward near the end of the week.
There is some uncertainty in this, however, as there are some
differences between global models regarding another surface trough
that could develop north of the islands mid- to late-week.

&&

.AVIATION...

Light to locally moderate trades bringing periods of MVFR 
cond in isol SHRA across windward and mauka locations. Winds will
diminish into a land/sea breeze pattern increasing clds and 
SHRA across leeward and interiors of the islands. MVFR possible 
in any SHRA, otherwise VFR prevails.

No AIRMETs in effect.

&&

.MARINE...

A trough just north of the coastal waters is moving southeast and
will move over the Kauai Monday. As the trough moves over Kauai, 
moderate northeast trade winds will fill in over Kauai waters, 
while elsewhere light to gentle east to southeast winds are 
expected through Monday night. Tuesday through Thursday light to
gentle southeast flow across the zones will also give way to 
localized land and sea breezes. Moderate trades will fill back 
from east to west at the end of the weak as strong high pressure 
builds far northeast and drifts south. 

The current moderate north-northwest swell that peaked well above 
High Surf Advisory (HSA) levels today has begun to decline 
quickly this evening and will continue to decline through Monday. 
The HSA and the Small Craft Advisory for seas above 10 feet has 
been cancelled.

A small medium to long period northwest (320 deg) swell is expected
to fill in through the day Monday, peak Monday night and slowly 
decline through the week. A small, long- period southwest swell 
has started to fill in with long period 16 second forerunners. The
swell is expected to peak Monday before subsiding Tuesday. 
Another small long- period southwest (200 deg) swell is possible 
by the later half of next week. Surf along east- facing shores 
will remain below average through the week.

Peak high tides associated with the lunar cycle will lead to minor
coastal flooding along shorelines and low lying coastal areas
starting Tuesday through the weekend. Coastal flooding will
coincide with the daily peak tide each afternoon.

&&

.FIRE WEATHER...

Light winds and increased showers will mitigate any fire weather
concerns through the week.


&&

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

&&

$$


UPDATE...Pierce
DISCUSSION...Vaughan
AVIATION...Walsh
MARINE...Shigesato