874
FXHW60 PHFO 010138
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
338 PM HST Sun Nov 30 2025

.SYNOPSIS...
A trough northwest of Kauai will maintain a ridge over the islands
resulting in minimal shower activity and light southeasterly winds.
Another front will approach and stall northwest of Kauai on Tuesday,
bringing clouds and showers to the western end of the island chain
Wednesday. More typical trade wind weather with showers favoring
windward and mountain areas will become reestablished Thursday
into the weekend.

&&

.DISCUSSION...
The forecast has been updated to reflect the latest National Blend
of Models (NBM), but the changes are minimal. There remains good
agreement with the models in the short term, but significant
differences in the ECMWF and GFS global models Wednesday onwards.

A surface and upper level ridge over the islands is maintaining
light southeasterly flow with a stable airmass in place. This
results is localized land and sea breezes and minimal shower
activity. The surface ridge has been pushed over the islands due
to a trough to the northwest which is expected to weaken and be
pushed to the northeast by another front currently far to the
northwest of the main Hawaiian islands.

The GFS and ECMWF are in good agreement with this next front
approaching from the northwest Tuesday. Both models bring pre-
frontal convergence bands to the northwest of Kauai Tuesday night.
The GFS stalls the front to the northwest of Kauai, while the
ECMWF brings the front over the Garden Isle, with additional
moisture being drawn northward over the Oahu and parts of Maui
County. For now the forecasts falls more in line with the GFS in
keeping the bulk of the shower activity west of Kauai.

The global models have some significant differences during the
second half of the week. Both models show the front dying and
being replaced by a surface trough. The GFS goes on to form a low
pressure system along the trough, west of the islands, with the
low moving to the west. The GFS also develops a strong upper level
low in conjunction with the surface feature. The ECMWF is slower
to develop a low along the trough, and when it does so, it
develops one north of the islands that lifts northward. While the
models show significant differences during the second half of the
week, they remain in decent agreement with a ridge north of the
islands allowing trade winds to build back in over the
islands. Accompanying the trades would be showers focused over the
windward and mountains areas.

The upper level feature from the GFS could spell increased winds
over the Big Island Summits Thursday on through the weekend.
Currently the forecast keeps winds below advisory levels for the
summits, however will have to watch future model runs to see how
things may play out.


&&

.AVIATION...
Light southeasterly flow will continue through the forecast period
with local sea breezes during the day and land breezes at night.
VFR conditions expected through Monday under a relatively dry and
stable air mass.

No AIRMETs are in effect and none are expected.


&&

.MARINE...

Ridging will remain in place over the area for the first half of
the week, maintaining light to moderate southeast background
winds. This pattern will allow for daytime sea breezes and
nighttime land breezes along waters adjacent to the coasts.
Meanwhile, an extra large northwest swell that peaked Sunday
morning will decline over the next day or so, but will produce
seas above Small Craft Advisory (SCA) levels for exposed waters
through midday on Monday. A Small Craft Advisory remains in effect
until that time, but seas will quickly fall below SCA levels
Monday afternoon into Monday night as the swell continues to fade.
On Wednesday, a front will approach Kauai from the northwest, but
guidance continues to indicate that it will weaken and then
retreat back to the west during the latter part of the week.
Easterly trade winds will finally return Friday into the weekend
as surface high pressure builds northeast of the area.

The current, extra-large, long-period northwest (310-320 degree)
swell peaked earlier Sunday and will slowly decline tonight
through Monday. With that said, as of Sunday afternoon the Waimea
Bay buoy 51201 continues to report impressive northwest swell
energy at 12-15 feet, 17 seconds. This swell is expected to
slowly lose energy tonight, but it will continue to produce
warning level surf throughout the night and into early Monday.
Therefore, the High Surf Warning remains in effect through noon on
Monday for exposed north and west facing shores of most islands.
Surf is then expected to drop to advisory levels by Monday
afternoon as the swell energy eases. Another large, long period
northwest swell (310-330 degree) is forecast to fill in on
Wednesday, peak Thursday, then slowly subside on Friday. Surf may
once again approach warning levels.

East shore surf will remain small through the weekend due to weak
winds. Some south facing shores experienced a small amount of
westerly wrap from this weekend`s large northwest swell on Sunday,
but this will ease by Monday and south shore surf will remain
small throughout the next few days.


&&

.FIRE WEATHER...
Rather dry conditions are expected to persist through Tuesday.
Winds will be light and variable under a stable land and sea
breeze pattern, preventing critical fire weather thresholds from
being approached. With the inversion holding around 6,500 ft, very
dry conditions will persist on the upper elevations of the Big
Island and Maui.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Warning until noon HST Monday for Niihau-Kauai Leeward-
Waianae Coast-Oahu North Shore-Maui Windward West-Kona-Kohala-
Kauai North-Molokai Windward-Molokai North-Molokai West-Maui
Central Valley North-Windward Haleakala.

Small Craft Advisory until noon HST Monday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters-Alenuihaha Channel-Big Island Windward
Waters.


&&

$$


DISCUSSION...M Ballard
AVIATION...Ahue
MARINE...Vaughan
FIRE WEATHER...M Ballard