255
FXHW60 PHFO 020200
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
400 PM HST Mon Dec 1 2025

.SYNOPSIS...
Stable and dry conditions with light southeasterly background
winds will continue for the first half of the week. This will
result in daytime sea breezes and nighttime land breezes each day.
A weakening front approaching from the northwest could increase
shower chances for the western islands Wednesday through Thursday,
though there remains some uncertainty. Trade winds will build
back into the region and strengthen from Thursday onward, bringing
back periods of passing showers to windward and mountain areas
that will favor the typical overnight to early morning hours.

&&

.DISCUSSION...
This afternoon, multiple low pressure circulation centers can be
seen on regional satellite imagery in the North Pacific, near and
north of 40N far north of the main Hawaiian Islands. A long
surface frontal boundary stretches from the southernmost of these
low pressure circulations southwestward to the International Date
line to near 160E. High clouds ahead of the front, which is
currently located about 350nm northwest of Kauai, have begun
streaming over the western end of the state today. Meanwhile, a
high pressure ridge remains in place over the island chain, which
has resulted in yet another day of stable conditions and light
southeasterly background winds prevailing over the state. Given
the light background flow, daytime sea breezes have increased
interior clouds over the islands today, but these interior clouds
will clear tonight as land breeze circulations resume. Rainfall
has been scarce within this dry, stable regime.

This stable pattern with light southeasterly background winds will
continue for most areas through at least late Tuesday into early
Wednesday. Throughout this time, daytime sea breezes will increase
interior clouds over the islands each day, followed by land
breezes clearing skies over the islands each night. Shower chances
will remain limited, and any showers that do occur would be
light.

Global models continue to show that the aforementioned cold front
to our northwest will gradually weaken as it approaches over the
next couple of days. It is then expected to move near Kauai and
stall on Wednesday. As this occurs, shower activity will likely
increase over Niihau and Kauai for 12 to 24 hours, until the front
breaks apart and drifts back westward away from the islands.
Differences between the various global models remain, with the
ECMWF notably showing wetter trends for the islands in Kauai
County. The GFS, however, continues to favor a drier solution
where the weakening boundary stalls and then moves back westward
away from the state before reaching the Garden Isle.

A high pressure system will build in north of the state for the
second half of the week, increasing easterly trade winds across
the region. Expect some southeasterly winds to linger on Thursday
morning, with winds becoming more easterly and stronger from
Thursday night into next weekend. As the ridge over the islands
lifts northward, our typical trade wind shower activity returns
with brief passing showers forecast along windward and mountain
areas, favoring the overnight to early morning hours each day.

&&

.AVIATION...
A light southeasterly wind regime will continue through Tuesday,
allowing daytime sea breezes and overnight land breezes to occur.
VFR conditions are expected under a relatively dry and stable air
mass through Tuesday. A thin veil of high clouds will move over
the state from west to east starting this evening.

No AIRMETs are in effect and none are expected.

&&

.MARINE...
A weak surface ridge will remain over the area through Tuesday
and maintain light to moderate southeast background flow. This
pattern will allow for daytime sea breezes and nighttime land
breezes along waters adjacent to the coasts. A cold front is
projected to approach Kauai from the northwest on Wednesday and is
expected to stall and quickly weaken to a trough by late
Wednesday. The trough is then expected to retrograde back
westward towards the end of the week as a ridge of high pressure
builds north of the state. Moderate to locally strong easterly
trade winds is expected to return Friday into Saturday.

The current, large, long-period northwest (310-320 degree) swell will
steadily decline through tonight. A High Surf Advisory is now in
effect through tonight for exposed north and west facing shores of
most islands. A series of northwest to north-northwest (310-330
degree) swells are expected during the second half of the week, with
each pulse becoming slightly bigger and veering towards the north-
northwest direction. The first pulse will be filling in on
Wednesday and will be more of a medium period swell out of the
northwest. Surf heights may approach advisory thresholds, but at
this time we are expecting surf heights to stay just below
advisory thresholds on Wednesday. A slightly larger and longer
period pulse is expected on Thursday out of the northwest followed
by a slightly larger north-northwest on Friday. Surf heights
should exceed advisory thresholds around Thursday with surf
heights likely holding above advisory thresholds through Saturday.

East shore surf will remain small through Thursday due to weak
winds, then become choppier as trade winds increase Friday through
the weekend. Expect minimal background energy for south facing
shores through much of the week.

&&

.FIRE WEATHER...
Critical fire weather conditions are not expected this week.
Although stable and dry conditions will persist through mid-week,
winds will be light and variable, preventing critical fire weather
concerns. Locally breezy trades will return during the second
half of the week, but increased relative humidity is expected.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 AM HST Tuesday for north and west
facing shores of Niihau, Kauai, Oahu, and Molokai, for north
facing shores of Maui, and for west facing shores of the Big
Island.

&&

$$

DISCUSSION...Vaughan
AVIATION...DT
MARINE...Kino
FIRE WEATHER...Vaughan