971
FXHW60 PHFO 021401
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
401 AM HST Sun Nov 2 2025

.SYNOPSIS...
A rapidly weakening cold front approaches the Hawaiian Islands
from the north today. This low level frontal cloud band will stall
out near the island of Kauai and weaken into a trough later today.
The stronger upper low will begin to drift slowly westward,
enhancing shower activity over windward mountain areas into
Monday. A weak ridge aloft will slowly fill in over the region
decreasing shower trends a bit from Tuesday into Thursday. An
upper level trough will drop in from the northwest on Friday,
likely enhancing trade wind showers before a shallow front moves
into the northwest islands by next weekend.

&&

.DISCUSSION...
In the big picture satellite imagery this morning we see a
weakening cold front approaching the island of Kauai at the
surface, while a cold unstable upper low enhances shower activity
over windward mountain areas statewide. A few thunderstorms are
possible near Kauai and Niihau today as the low level frontal
trough interacts with the unstable upper low. Subsidence
temperature inversion heights, measured at 2 AM HST (12Z) this
morning at Hilo and Lihue, range from 7,000 feet and 10,000 feet
respectively. These higher inversion heights over the western half
of the state are due to the closer proximity to the unstable upper
level cold core low. Rain shower activity today will remain the
highest over Kauai County with more passing showers forecast to
spread across the rest of the island chain.

The surface cold front will weaken into a trough later today and
the surface trough will follow the upper level low as the system
begins to drift westward away from Hawaii through Monday. Cloud
tops may briefly reach the highest summits of Mauna Kea and Mauna
Loa on the Big Island on Monday and Monday night. Freezing
temperatures at summit level may produce some light rime icing
concerns during this time period as supercooled cloud drops freeze
on contact with roadways, vehicles and buildings above the 11,000
foot elevation level. A Winter Weather Advisory for the Big
Island summit zones may be needed for Monday due to this potential
icing threat.

Global models continue to show a weak ridge filling in aloft over
the state with a slight decrease in statewide shower activity
from Tuesday through Thursday. Trade wind will also see a subtle
increase into the moderate to locally breezy range during this mid
week time period.

Another upper level trough moves in from the northwest on Friday,
divergence aloft will spread over the islands lifting trade wind
temperature inversion heights, and increase shower trends from
Friday into the weekend. Another weakening cold front will
approach the islands from the north and stall out near Kauai and
Oahu next weekend. Islands within this stalling frontal band will
see cloudy skies and showers. More island by island forecast
details as the time period grows shorter. Stay tuned.

&&

.AVIATION...
Moderate trade winds will continue through Monday as a weakening
cold front and unstable upper level low moving in from the
northwest stalls out near the island of Kauai. A few thunderstorms
are possible today near Kauai and Niihau today and tonight with
this system. Wet weather conditions with periods of MVFR
conditions remain in the forecast for Kauai and Niihau. Additional
periods of showers should be expected across windward airfields
over all islands with brief periods of MVFR conditions in any
shower activity. Expect improving trends on Monday as this system
begins to drift westward away from the state.

AIRMET Sierra was issued for mountain obscuration over the island
of Kauai, as a weak cold front and unstable upper low moves into
the region.

&&

.MARINE...

A front is sagging southward over the northwest portion of the
offshore waters early this morning, bringing pockets of strong
(near gale) breezes, along with isolated to scattered
thunderstorms. Some of these thunderstorms may enter the coastal
waters near Kauai later today through tonight. The front is
expected to stall and then get pushed to the west as high pressure
builds to the north by Monday, increasing trade winds to moderate
to locally fresh speeds. Winds will likely remain below SCA
levels until Tuesday or Wednesday. However, seas are expected to
reach SCA levels later this morning as a mix of northwest and
north swells build into the northwestern end of the island chain.
By the later half of next week, a front far to the north could
disrupt the trade winds once again.

Surf along north facing shores will build today as a mix of
medium to long period north-northwest swells (320-330 degrees)
fill in across the area. A medium period north-northeast swell
will fill in later today into the evening hours associated with
the approaching front with near-gale winds, that will primarily
impact the western end of the state. This mix of swells is
expected to maintain HSA level surf through tonight before
gradually fading early this week and so a HSA is in effect through
6 AM HST Monday for most north and west facing shores of the
smaller islands. A moderate long period north-northwest swell (340
degrees) is then possible around the middle of next week.

Surf along east facing shores will remain small to moderate through
the morning, and then may be impacted by the medium period NNE
swell mentioned above. South shore surf will remain small through
early next week before building slightly mid to late week as a
long period south-southwest swell (190 degrees) fills in across
the region.

&&

.FIRE WEATHER...
Increased relative humidity values and light trades will maintain
below critical fire weather conditions the next several days.
Temperature inversion heights near the Big Island and Maui will
range from 7,000 to 8,000 feet today.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 AM HST Monday for Niihau-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 Monday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Kaiwi Channel-Maui County Windward Waters.

&&

$$

DISCUSSION...Bohlin
AVIATION...Bohlin
MARINE...Farris
FIRE WEATHER...Bohlin