817
FXHW60 PHFO 130149 CCA
AFDHFO

Area Forecast Discussion...CORRECTED
National Weather Service Honolulu HI
349 PM HST Sun Oct 12 2025

.SYNOPSIS...

An upper-level low centered several hundred miles north of the
state will continue to move south through midweek, then weaken and
slide off to the west. This will bring a chance for heavier
showers and a few thunderstorms from Wednesday into Friday
evening. Relatively light southeast surface winds continue through
Tuesday, with stronger trades kicking in Wednesday into lasting
into next weekend.

&&

.DISCUSSION...

Another afternoon of sea breezes and isolated showers mainly in
leeward areas is well underway. That pattern will generally
continue through Tuesday. The largest area of showers as of 3 PM
HST was over southwest Kauai. In addition, a band of higher
clouds, associated with the entrance region of an upper level jet,
was moving SW to NE.

A strong upper level low and its surface reflection will continue
to move south through Wednesday afternoon, reaching the western
islands (it will be centered roughly overhead) before sliding off
to the west and weakening late this week and into next weekend.
This will bring cooler air aloft, increasing instability and the
chance for stronger showers and thunderstorms, especially
Wednesday through Friday evening. We have gone ahead and
introduced thunderstorms into the forecast as confidence is high
that they will occur. The most likely area is the western part of
the state, but we can`t rule out storms in the east at this time.

The other significant change this coming week will be the surface
winds. Relatively light southeast winds will give way to easterly
trades Wednesday. Wind speeds will increase, especially in the
usual topographically driven areas straights. Small craft
advisories may be needed beginning Thursday.

&&

.AVIATION...

Light E to ESE winds are prevailing across the state, which has
resulted in localized sea breezes during the day. Low clouds and
showers remain limited overall, though some low clouds and showers
will remain possible through early evening over island interiors
and select leeward locations. VFR flight conditions are expected
to prevail at most locations. Meanwhile, an upper jet is producing
a band of high clouds streaming over the central and eastern
islands. This jet is expected to weaken and push east of the area
through tonight, so anticipate that high cloud cover will diminish
by early Monday.

Another day of light background winds and daytime sea breezes is
expected on Monday, increasing interior clouds and showers during
the day. Overnight, land breezes are forecast to diminish cloud
cover over the islands.

There are currently no AIRMETs in effect, and none are
anticipated at this time.

&&

.MARINE...
A trough north of the area will settle in the proximity of the
islands the next couple of days. Troughing will likely lay across
the far west waters and, as energy from the north dives south into
the trough, the chances for mid to late week western water isolated
to scattered thunderstorms will increase. Slightly strengthening
surface high pressure centered around a thousand nautical miles
northeast of the state will produce a tight enough downstream
pressure gradient by Wednesday to result in more water-wide
moderate trade winds.

Long period forerunners from an approaching northwest (320
degree) swell reached the offshore 51001 and 51101 buoys late this
morning. This has a moderate size, long period swell reaching
Kauai and Oahu this evening, Maui around Midnight Monday. Swell
will fill in around all islands during the overnight hours and
produce advisory level surf along many north and west-facing
shores of the smaller islands by late Monday morning. A High Surf
Advisory will be in effect from Monday morning through Tuesday
afternoon to account for over double head high surf that should
peak along many north and west-facing shores early Tuesday. Surf
will begin to gradually fall from Tuesday night through Thursday.

A series of very small, medium period southern swell impulses
coming from a couple of fast-moving southern gales passing south
of New Zealand will pass through this week.

East-facing shore wind wave chop will be small the next couple of
days. More rough surf will occur later this week as trades build
over and upwind of the islands.

Water levels will continue to gradually lower through Monday.
There may be some minor flooding within low laying areas during
Monday`s high tide.

&&

.FIRE WEATHER...
Light winds and isolated showers will help maintain fire weather
below critical thresholds for the next several days. Inversion
heights will range from 6,000 to 8,000 feet.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory from 3 AM Monday to 6 PM HST Tuesday 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.

&&

$$


DISCUSSION...Parker
AVIATION...Vaughan
MARINE...Blood
FIRE WEATHER...Parker