Royal Kunia, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

790
FXHW60 PHFO 221421 CCA
AFDHFO

Area Forecast Discussion...CORRECTED
National Weather Service Honolulu HI
421 AM HST Mon Dec 22 2025

.SYNOPSIS...

Easterly trade winds will continue to strengthen to breezy levels
by tonight and hold through Tuesday. A remnant front moving in
from the north will increase showers tonight into Tuesday with
mainly light to moderate showers focusing along windward and mauka
areas with periods of showers spilling over to leeward sides. A
drier more typical locally breezy trade wind pattern is expected
from Wednesday to Thursday. A cold front will become nearly
stationary northwest of the state Friday into the weekend,
veering winds out of the east southeast. This lighter pattern
will allow for a hybrid trade wind and sea breeze regime to set up
over the weekend. A wetter pattern shift may be possible early
next week.


&&

.DISCUSSION...

A storm force low far northwest of the state is sending some high
clouds over the western half of the island chain this morning.
A ridge of high pressure north of the state is generating locally
breezy easterly winds across the state with limited low level
clouds and showers along windward and mauka areas. Trade winds
will strengthen to breezy levels speeds later this afternoon and
early evening as the ridge continues to strengthen. A remnant band
of clouds will push through the state tonight by these stronger
easterly trade winds during this time. Expect increasing clouds
and showers along windward and mauka areas with a few showers
spilling over into leeward areas tonight into early Tuesday
morning. Chances of showers will trend down through the day
Tuesday after this band swiftly moves through the state.

The ridge of high pressure will weaken Christmas Eve through
Christmas Day as the storm force low far northwest of the island
lifts north. Trade wind speeds will gradually ease to locally
breezy speeds during this time. Drier and more stable conditions
will develop statewide as mid to upper level ridging develops over
the state.

Friday the storm low will track east far north of the state with
a trailing frontal boundary becoming nearly stationary northwest
of Kauai by Friday. The proximity of this frontal boundary will
place the weak surface ridge over the state veering winds out of
the east southeast. Winds will become light to gentle over the
western half of state while more locally breezy east southeast
winds hang around the eastern half of the state. This setup will
lead to a hybrid trade wind sea breeze pattern under a mostly dry
and stable airmass as mid to upper level ridging holds over the
state.

The extended range model guidance shows deep upper level
troughing could lead to more instability developing over the
western half of the state over the weekend into early next week.
In addition, southerly flow at the surface will draw in more
moisture, increasing chances of showers over the weekend into
early next week. No significant weather is expected at this time
but will continue to monitor for any changes.


&&

.AVIATION...

The trade winds will gradually strengthen to breezy levels today
across the state. AIRMET Tango will likely be issued later today
for low level turbulence downwind of terrain as winds continue to
strengthen. Increasing showers embedded within the trade winds
will bring brief MVFR conditions to windward and mauka areas,
especially this evening through early morning Tuesday. Otherwise,
VFR will prevail.

There are no AIRMETs currently in effect.


&&

.MARINE...
High pressure continues to build into the islands from the north,
increasing easterly trade winds lasting into Wednesday morning.
Trades then ease and wind directions will veer from a more
southeasterly to southerly direction from Wednesday night onward
as a low pressure system approaches from the northwest, driving
the surface ridge axis over the islands. Briefly stronger winds
are expected behind an old remnant frontal cloud band moving into
Hawaiian waters from the north starting tonight through Tuesday.
The Small Craft Advisory for the typical windier waters and
channels near Maui and the Big Island remains in effect, this SCA
will expand in coverage for most coastal waters starting tonight
due to increasing trade wind speeds.

The current medium period north to north-northeast (360-020
degree) swell energy continues to slowly decline today and swell
heights and periods are dropping at offshore and coastal buoys
this morning. The forerunners associated with the next moderate
north to north- northeast (360-020 degree) swell are forecast to
arrive by late Wednesday, bringing moderate surf to favored
northern exposures Wednesday night into Friday. Surf heights along
west facing shores will be limited as the north-northeast swell
direction and medium period swell energy is less favorable. A
Marine Weather Statement may be needed for this next swell
affecting north facing harbors possibly by Wednesday night,
especially impacting the harbors of Kahului and Hilo.

Returning trades will build surf along E facing shores peaking
with stronger trades on Tuesday. The north-northeast swell will
likely boost choppy and rough surf heights a bit along east
facing shores through Wednesday. Surf along south shores remains
tiny with fleeting background south to southwest energy through
the week.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory from 6 PM this evening to 6 PM HST Tuesday
for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward
Waters-Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters-
Kaiwi Channel-Maui County Windward Waters-Maui County Leeward
Waters.

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


&&

$$


DISCUSSION...Almanza
AVIATION...Almanza
MARINE...Bohlin