951
FXHW60 PHFO 060146
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
346 PM HST Fri Dec 5 2025

.SYNOPSIS...
Moderate trades deliver limited clouds and showers windward and
mauka into next week.

&&

.DISCUSSION...

ESE flow in the low and mid-levels is supplying adequate moisture
for frequent showers over favored slopes of Windward Big Island and
Maui this afternoon where 24 hour rainfall totals have ranged from a
couple tenths to around 1.5". Meanwhile terrain-parallel flow has
allowed persistent showers to develop over the Ko`olau range on
Oahu while the sea breeze has also capitalized on resident
moisture allowing showers to develop over and leeward of the
Waianae Range. All shower activity will begin diminishing this
evening, the latter with the loss of diurnal heating and the
former as winds back to easterly and usher moisture west of the
islands.

A much drier airmass lurks immediately upstream of the island as
evidenced by recent water vapor imagery and a limited coverage of
low clouds on visible. This airmass will pivot into the area tonight
into Saturday bringing considerably drier conditions as sea level
dewpoints fall from the mid to upper 60s into the low 60s by
evening. Moderate trades during this time will be accompanied by
limited light showers mostly sunny skies with the exception of the
Big Island where clouds and a few light showers will favor upslope
areas Saturday afternoon. Highly stable, moderate trades then
continue into the middle of next week with very limited rainfall
windward and mauka.

Extended guidance teases a more active or at least more interesting
pattern developing during the second half of next week beginning
with surface winds veering to southerly by Thursday in response to a
frontal wave developing northwest of the islands. Initially benign
other than an increase in dewpoints, the attendant cold front sweeps
into the forecast area late in the period bringing a round of
showers and falling dewpoints. Though differences abound at the
surface, synoptically the global models point toward blocking high
pressure establishing over the western Aleutian Islands with a
tendency for low pressure to establish near/upstream of the islands
heading into mid December.

&&

.AVIATION...

Moderate to locally breezy east-southeasterly winds will
gradually weaken through Saturday as the surface high to the far
northeast weakens and drifts further eastward. With the slightly
veered flow, showers will continue to stream into south and east
facing slopes of all islands and convergent boundaries downwind of
island terrain will provide a source of isolated to scattered
showers to leeward areas of some of the smaller islands through
this evening. MVFR, or even brief IFR conditions will be possible
in these showers. Drier air will move in overnight allowing for
limited shower activity focused over windward and mountain areas
tonight through Saturday, with VFR conditions generally prevailing.

AIRMET Sierra for mountain obscuration is in effect for all of
Oahu and east and south facing slopes of the Big Island.

AIRMET Tango is in effect for moderate low level turbulence over
and downwind of island terrain.

Both of these AIRMETs will likely be able to be cancelled this
evening.

&&

.MARINE...

A surface trough west of Kauai will continue to gradually weaken
and retrograde westward away from the islands tonight into the
weekend. Meanwhile, surface high pressure is building northeast of
the state. This will allow moderate to locally strong east to
east-southeast winds to persist into Saturday. A Small Craft
Advisory (SCA) remains in effect through tonight for most Hawaiian
coastal waters due to a combination of winds and seas of 10 ft or
greater. By Saturday morning, however, seas are expected to
decline below SCA levels as northwest swell energy fades.
Therefore, the SCA will be reduced to the typically windy waters
of Maui County and the Big Island for the day on Saturday.
Moderate trades will continue through the first half of the week,
followed by lighter east-southeast flow during the second half of
the week.

A moderate, medium period northwest swell that was on a slight
decline earlier today has been followed by a slightly longer
period northwest reinforcement this afternoon. This has resulted
in an uptick in surf along north and west facing shores during the
day today. Based on observations from both the Waimea buoy and
offshore buoy 51001, the High Surf Advisory (HSA) for north and
west facing shores has been extended through 6AM HST Saturday
morning, and surf heights have been updated accordingly. This
northwest swell energy will gradually fade this weekend, bringing
surf back down below average Sunday and Monday. Another northwest
swell arriving late Tuesday or Tuesday night could bring surf
back up to near or slightly above advisory levels again for the
middle part of the week for north and west facing shores.

Choppy east shore surf will remain small and decline this weekend
as trades ease. Expect minimal background energy for south facing
shores through the next few days, other than a slight bump this
weekend.

Peak monthly tides combined with water levels that are running
higher than predicted will likely lead to minor flooding along
the shoreline and in low-lying coastal areas. Coastal flooding is
possible around the daily peak tide, which will be during the
early morning hours. This could also magnify effects of the high
surf on coastal areas along north and west facing shores around
the same time frame.


&&

.FIRE WEATHER...
The inversion slopes from around 8kft at Lihue to 11kft at Hilo.
Drier air filters into the area for Saturday but moderate trades
unlikely to reach the critical fire threshold. Dry weather and
relatively light winds continue well into next week.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 AM HST Saturday for Niihau-Kauai
Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kauai
North-Molokai Windward-Molokai North-Molokai West-Maui Central
Valley North-Windward Haleakala.

Small Craft Advisory until 6 AM HST Saturday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Channel-Oahu Windward Waters-
Kaiwi Channel-Maui County Windward Waters-Big Island Windward
Waters.

Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...JVC
AVIATION...Farris
MARINE...Vaughan
FIRE WEATHER...JVC