Nanakuli Beach Park, Hawaii Weather Forecast Discussion

666
FXHW60 PHFO 271259
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
259 AM HST Sat Sep 27 2025
.SYNOPSIS...
Light trades return today with a chance of afternoon showers over
the interior and western portions of Kauai and Oahu. Stability
then steadily increases heading into next week as moderate trades
take hold.
&&
.DISCUSSION...
Slug of low-level moisture west of the Big Island is advancing
northwestward beneath a canopy of high clouds aloft. Veered flow
in the lower levels will draw this moisture over the remainder of
the island chain on Saturday. At the same time, weak returning
trade winds will give way to a hybrid sea breeze pattern in the
afternoon setting the stage for afternoon showers focused over
leeward slopes of Oahu and Kauai. With the resident upper low
still in close proximity, slightly cooler-than-normal mid-level
temps and cyclonic flow aloft may allow for a few heavy showers.
Localized nuisance type flooding cannot be ruled out. 590+dm mid-
level ridging then builds into the area during the remainder of
the weekend into next week favoring a return to a moderate, high
stability trade wind pattern with clouds and showers favoring
windward and mauka slopes, particularly overnight. A remnant
frontal moisture band embedded in the trades is modeled to bring
an uptick in shower coverage midweek.
&&
.AVIATION...
A surface trough near Kauai continues to slowly move westward
this morning. Shower coverage looks sparse, but lingering
instability from the upper low could still allow some heavier
showers to develop and drift ashore from the south. The afternoon
could also see some shower development over interior and leeward
areas. Trade winds will start filling back in later today into
tomorrow, shifting showers and MVFR vis/cigs back to typical
windward and mountain areas.
No AIRMETs are in effect, although mtn obscuration is possible
this afternoon with any shower development.
Light icing is possible over Maui and Big Island in lyr 150-FL260
due to high level clouds filling in over the area from an upper
level jet. These conditions will remain possible through the
morning.
&&
.MARINE...
A surface low associated with a trough west of the offshore waters
will continue to drift west and weaken through Sunday. A chance for
isolated to scattered thunderstorms will remain over the northwest
offshore waters through the weekend. Moderate to locally fresh easterly
trade winds will build in from the east to west today. Trade winds
look to gradually strengthen to locally strong speeds, bringing
back the Small Craft Advisory (SCA) for the windier waters and
channels around Maui County and the Big Island Sunday through the
first half of next week.
Surf along south facing shores will gradually build as a small to
moderate medium to long period south swell fills in today and
looks to hold through the weekend. A series of small medium period
south swells will keep surf from going flat through the middle of
next week.
Fading energy from the north-northeast swell will continue to drop
today, as a small medium to long period northwest swell is
expected to fill in and hold through the evening before declining
Sunday. A series of tiny to small swells from the north and
northwest will trickle in through next week Wednesday.
Surf along east facing shores should increase Sunday as trade
winds return, along side a tiny medium period easterly swell
generated from Hurricane Narda far to the east.
&&
.FIRE WEATHER...
Conditions remain below the critical fire weather threshold
through the weekend as light winds persist through Saturday and
high RH associated with resident low pressure persists. Moderate
trades and drier conditions expected by next week.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...JVC
AVIATION...Shigesato
MARINE...Tsamous
FIRE WEATHER...JVC

NWS HFO Office Area Forecast Discussion