066
FXHW60 PHFO 020152
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
352 PM HST Mon Sep 1 2025

.SYNOPSIS...
Showers near Kauai and over the Kona slopes of the Big Island will
diminish overnight as light to moderate trade winds bring a drier
air mass over the island chain. For the remainder of the week,
continued light to moderate trade winds and generally stable
conditions will bring modest rainfall to windward areas. While
most leeward areas will be rather dry, sea breezes will produce
afternoon clouds and a few showers over terrain, especially on
the Big Island.

&&

.DISCUSSION...
An area of moisture within a light to moderate trade wind flow
has been producing some active showers over the western end of the
island chain this afternoon. Aided by slight instability produced
from a nearby upper-level low northwest of the state, a few
showers briefly formed along the Waianae Mountains on leeward
Oahu around midday, but as drier air pushed westward, this
activity has largely moved over interior Kauai and waters just to
the south. This moisture has also remained hung up on leeward Big
Island and has fueled scattered showers, some briefly heavy, in
and around Kailua-Kona. Expect shower activity on Kauai and
leeward Big Island to linger into the evening then diminish
overnight. Elsewhere, the stable trade wind flow will produce
minimal windward rainfall and mostly dry conditions leeward.

A stable and somewhat dry light to moderate trade wind flow will
become established on Tuesday. A weak surface ridge parked roughly
300 miles north of Kauai will maintain trades near current
strength. The upper-level low will begin to creep northward and
allow a strong mid-level ridge, already in place over the eastern
half of the island chain, to bring increasingly stable conditions
to the entire state. The moisture currently fueling showers
around Kauai and over the Kona slopes will move west of the
islands, and the incoming drier air mass will produce minimal
showers over windward slopes. Most leeward areas will be rather
dry, but sea breezes will produce afternoon clouds and a few
showers, mainly on the Kona slopes of the Big Island. Little
change is expected to the somewhat dry trade wind flow through
the coming weekend.

The latest National Hurricane Center forecast has East Pacific
Tropical Storm Kiko strengthening into a hurricane before crossing
into the Central Pacific Friday or Saturday. It remains too early
to tell what, if any, impacts this system might have on the local
weather as it nears the islands early next week.

&&

.AVIATION...
Beneath a partial coverage of cirrus aloft, the trade wind
inversion has trapped moisture in the 7-9kft layer which will
continue supporting SCT-BKN VFR cigs through tonight mainly from
Oahu to Kauai. Iso-sct aftn showers over select interior zones
will dissipate with the loss of heating this evening followed by
moderate trades that will deliver limited showers to windward and
mauka zones overnight. Little to no change expected for tomorrow.

&&

.MARINE...
A ridge of high pressure north of the state will remain displaced
to the south in response to large low far to the north. This will
maintain moderate trades through most of the forecast period,
with some localized sea breezes, especially across leeward waters.

Elevated surf will continue along north facing shores due to a
short- to medium-period north swell. This swell will quickly be
overshadowed by longer-period energy out of the northwest
starting tonight. The northwest swell will peak Tuesday afternoon.
A reinforcing pulse out of the north should arrive around the
same time the northwest swell arrives. A mix of north and
northwest swells are expected to continue thereafter, keeping
north shore surf elevated, but slowly declining, through Thursday.

Surf along south facing shores will continue to decline through
today as the south swell fades, despite a slight boost from short-
period southeast energy. Below average surf is expected to
continue along east facing shores persisting through early next
week.

Peak monthly high tides, combined with water levels running higher
than predicted, may lead to minor flooding along the shoreline and
in low-lying coastal areas toward the end of next week. Coastal
flooding may be possible around the daily afternoon peak tide.

&&

.FIRE WEATHER...
Even as rather dry conditions return tonight and Tuesday, trade
winds will remain in the light to moderate range and below the
critical threshold this week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Wroe
AVIATION...JVC
MARINE...TS
FIRE WEATHER...Wroe