Royal Kunia, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

863
FXHW60 PHFO 250132
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
332 PM HST Wed Dec 24 2025

.SYNOPSIS...
Stable easterly trade winds will decrease slightly and focus
limited rainfall along mainly windward slopes through Friday.
Somewhat dry conditions will persist and high clouds will
thicken on Saturday as winds diminish and shift southerly ahead
of an approaching front. The front will stall just northwest of
the islands and may bring an increase in showers to Kauai on
Sunday. A slow moving disturbance aloft will produce higher
chances of heavy showers early next week as trade winds rebuild.

&&

.DISCUSSION...
Stable and locally breezy easterly trade winds prevail. The
trades are being driven by a narrow high pressure cell centered
north of Hawaii with deep areas of flanking low pressure just off
the US west coast and just west of the Dateline. This amplified
pattern is supporting a ridge aloft over the region, which is
producing stable conditions with an inversion based between 5000
and 7000 ft. The stable trade wind flow has produced little
rainfall this afternoon from Kauai to Maui, but an area of shallow
moisture hung up on windward Big Island has managed to maintain
significant low clouds and squeeze out a tenth to a quarter of an
inch of rainfall.

Expect little change Christmas Day and Friday. Trades will
decrease slightly as the high moves to the east and sends a
trailing surface ridge toward the islands. The ridge aloft will
maintain stability, and no areas of moisture are noted in the
guidance, suggesting rather dry leeward conditions and modest
windward rainfall. Dew points will remain in the low 60s,
maintaining a somewhat cool feel.

Winds will diminish and shift out of the southeast and south
Friday night and Saturday as an approaching front pushes the
surface ridge near Kauai. The ridge aloft will begin to erode as
an approaching upper level trough sends thickening high clouds
over the state. Stable conditions should hang on as daytime sea
breezes produce spotty interior showers in the afternoon. Light
winds and somewhat dry and cloudy conditions will persist for most
areas on Sunday, but the above mentioned front will stall near or
just northwest of Kauai, supporting higher chances for some
showers on the Garden Isle.

Chances for unsettled weather increase early next week, though
significant uncertainty remains. The latest runs of the GFS and
ECMWF have been showing a strong zonal West Pacific jet stream
splitting near the Dateline and amplifying an upper level trough
and subtropical jet near Hawaii. Guidance has been depicting this
upper level trough moving slowly over the islands through next
Wednesday at varying strength, which leaves quite a bit of
uncertainty in resulting instability and heavy rain potential.
There is relatively good model agreement in showing surface high
pressure developing north of the state, which leads to higher
confidence that trades will rebuild. At this time, the uncertain
pattern favors unstable and wet trade winds that would place the
greatest potential for heavy rainfall over windward areas.

&&

.AVIATION...
Trade winds will gradually decrease over the next few days as
high pressure to the north begins to weaken. Limited shower
activity is expected, with VFR conditions prevailing.

&&

.MARINE...
High pressure far N of the islands and an associated surface ridge
to the NE will keep moderate to locally breezy trade winds in
place through at least tomorrow night. A Small Craft Advisory
(SCA) is in place for the windier waters and channels around Maui
County and the Big Island through tomorrow night and could be
extended as trade winds continue. A low to the far NW is forecast
to move E and push a cold front towards the offshore waters by
Friday, this will turn the winds slightly ESE. This weekend, the
cold front is expected to enter the far NW offshore waters and
push the surface ridge over the islands, effectively weakening
the winds and turning them more southerly.

Surf along north facing shores will remain small for the remainder
of the afternoon before a moderate, medium period north-northeast
(010-030 degrees) swell fills in this evening. This swell will
peak Christmas Day near High Surf Advisory levels, before
declining Friday. This swell has been filling in at the offshore
buoys through the day with most of the energy to be focused over
the eastern end of the state when it arrives. A Marine Weather
Statement is in place for moderate harbor surges at Kahului and
Hilo tonight through Christmas Day. A combination of the declining
north-northeast swell and a small long period west-northwest
swell will keep small surf through the weekend. West facing shores
will see a tiny, moderate period west swell hold through the day.
The next large long period northwest swell is expected over the
first half of next week but stay tuned as the system develops
northwest of the islands.

Rough and choppy surf along east facing shores will remain
elevated tonight before gradually declining as trade winds ease
slightly tonight. With the building north-northeast swell
expected this evening, exposed shorelines will see wrapping energy
through Friday. Surf along south facing shores will remain very
small through the week.

&&

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

&&

$$

DISCUSSION...Wroe
AVIATION...TS
MARINE...Tsamous