667
FXHW60 PHFO 280133
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
333 PM HST Sun Jul 27 2025

.SYNOPSIS...
Light to moderate trade winds will prevail through Monday as a
shallow area of moisture brings increased humidity and higher
shower chances to the central then western end of the island
chain. Locally breezy trade winds and rather dry conditions will
develop on Tuesday and Wednesday and will likely persist into next
weekend.

&&

.DISCUSSION...
Gentle to locally moderate trade winds continue to push an area
of shallow moisture over portions of the island chain. The trough
associated with the moisture has largely dissipated over the
islands but is strong enough to the north to ease the local
pressure gradient and keep trades lighter than normal. The trough
dropped up to a half of an inch of rainfall on windward Big
Island last night and has produced scattered showers on windward
Maui County today. Leeward and interior Big Island are
experiencing scattered showers this afternoon, and the moisture
was deep enough to trigger a few thunderstorms on the higher
elevations of Mauna Loa. Dew points on these islands have also
been elevated in the low 70s, leading to a humid feel. Meanwhile,
fewer showers and lower humidity have prevailed on Oahu and Kauai.

The area of moisture will creep westward to Oahu tonight and
Kauai on Monday. Humid conditions will develop on these islands as
dew points climb into the lower 70s, and while rainfall from
windward shower activity is not expected to be significant,
daytime sea breezes could trigger isolated briefly heavy leeward
showers Monday afternoon. Meanwhile, drier conditions will slowly
filter in on Big Island then Maui County, even though dew points
remaining in the upper 60s. Minimal windward showers are due over
the eastern end of the state, mainly windward, though the Kona
slopes of the Big Island may experience scattered afternoon
showers.

Trade winds will gradually strengthen Tuesday and Wednesday as
drier conditions develop. Even though a surface trough will
linger north of the state, Tropical Depression One-C (which is
forecast to become a tropical storm) passing well south of Hawaii
will help tighten the local pressure gradient and drive stronger
trades. There is still a bit of uncertainty as to how strong the
trades will get, but the latest guidance suggests locally breezy
winds will develop late Tuesday and be slightly stronger
Wednesday. Ridging aloft will strengthen during this time,
bringing a lower inversion that could contribute to gusty
conditions on Wednesday. Under these stable conditions, only
modest windward rainfall is expected, with dry weather favored
leeward.

Moderate to locally breezy trade winds will persist into next
weekend as surface high pressure holds north and northeast of the
state. Relatively dry trade wind weather is expected.

&&

.AVIATION...
Gentle trade winds with localized areas of nighttime land and
daytime sea breezes tonight into Monday as a surface trough
tracks west from near Maui to Kauai through the next 24 hours.

There are currently no AIRMETs in effect, but AIRMET Sierra for
mountain obscurations could be possible over windward areas of
Maui County amd Oahu overnight with the upstream clouds and
showers.

&&

.MARINE...
High pressure far northwest of the state will slowly build north
of the area throughout the week. Trade winds will maintain gentle
to locally fresh speeds through Monday then strengthen Tuesday
into Wednesday to moderate to locally strong levels. As the
trades strengthen, a Small Craft Advisory for the windier waters
and channels around Maui County and the Big Island is expected by
Tuesday or Wednesday. Trade winds could strengthen further by the
end of the week, which could cause the expansion of the Small
Craft Advisory to other coastal water zones.

Tropical Depression 01C located far southeast of the Big Island
is expected to pass far south of the state as a tropical storm
around the middle of the week. Minimal impacts are expected, but
some moderate southeast swells will be possible. Over the offshore
waters, Tropical Depression 01C could bring some isolated
thunderstorms for the far southern areas of the offshore waters.
For more info, please check the public advisories on Tropical
Depression One-C under WMO header WTPA31 PHFO and under AWIPS
header HFOTCPCP1. Forecast/Advisories on Tropical Depression One-C
are issued under WMO header WTPA21 PHFO and under AWIPS header
HFOTCMCP1.

South facing shores will remain small the next few days with
mainly background energy. A storm force low east of New Zealand
last week Wednesday (7/23) will send a moderate long-period south
swell, which should be filling in as early as Tuesday. This
initial south swell should peak on Wednesday near or slightly
above the summer average. A much stronger hurricane force low
developed southeast of New Zealand on Thursday (7/24) and tracked
northward while gradually weakening through today. This low should
send a long-lived south swell with forerunners arriving as early
as Wednesday and steadily building through Thursday. This swell
will likely peak late Thursday into Friday at High Surf Advisory
thresholds and gradually fade over the weekend into early next
week.

East facing shores will remain small through Monday before
slowly rising Tuesday through the rest of the week as trade winds
increase. Southeast swell from Tropical Depression One-C will
also be possible during the second half of the week. Flat summer
time surf will continue along north facing shores this week. An
out of season small long-period northwest swell will be possible
late next weekend from Typhoon Krosa currently located in the
western Pacific.

&&

.FIRE WEATHER...
Trade winds will remain weaker than normal and dew points will
remain elevated over portions of the state through Monday,
mitigating fire weather concerns. A rather dry, stable, and
locally breezy trade wind flow will develop late Tuesday or
Wednesday. A tropical cyclone passing well south of Hawaii during
this time is producing some uncertainty in the strength of the
winds for Wednesday, but near critical conditions are possible,
with elevated fire weather concerns persisting into next weekend.

&&

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

&&

$$

DISCUSSION...Wroe
AVIATION...Foster
MARINE...Kino
FIRE WEATHER...Wroe