Kapaa, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

640
FXHW60 PHFO 011349
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
349 AM HST Fri Aug 1 2025

.SYNOPSIS...
Breezy to locally windy trades, and rather dry and stable
conditions will persist today, and likely into Saturday. Clouds
and light showers will be focused over windward and mauka areas,
while most leeward areas remain dry. Stable trade winds will
gradually ease Sunday through Tuesday.


&&

.DISCUSSION...
No significant changes to the forecast or the forecast philosophy
with the morning package.

High pressure to the northeast, along with Tropical Storm Iona and
other low pressure to the south to southwest of the islands,
combined with a stable airmass over the islands with the inversion
around 6,000 feet, is continuing to tighten the pressure gradient
over the islands leading to breezy to locally windy trade winds.
Under these conditions, trades are being accelerated over and
downwind of terrain, with winds strong enough to continue the Wind
Advisory over portions of Maui County and the Big Island. Shallow
pockets of moisture being carried in on the trade wind flow will
continue to bring light rainfall accumulation mainly to windward
slopes, with leeward areas remaining dry.

Little change is expected tonight and Saturday, so confidence is
high that the Wind Advisory will be extended. The surface high
northeast of the state will strengthen slightly as it drifts
eastward, and a surface trough in the deep tropics will pass south
of the islands, keeping the pressure gradient rather tight. Modest
showers will remain confined to windward areas.

Trade winds will gradually decline Sunday into Tuesday as the high
drifts eastward and the local pressure gradient slowly relaxes.
The stable pattern of mainly windward and mauka showers should
persist as little organized moisture is depicted in the guidance.

Some uncertainty is introduced by the middle of next week. The
latest National Hurricane Center forecast depicts current east
Pacific Tropical Storm Gil weakening to a remnant low well east of
Hawaii early next week, and the GFS and ECMWF show a remnant
circulation passing near the state around Wednesday or so. It`s
too early to determine what, if any effects, this feature will
bring for island weather.


&&

.AVIATION...
High pressure to the northeast of the islands, combined with a
low pressure system to the south, will maintain breezy to windy
trade winds into the weekend. VFR conditions are expected to
prevail, however some passing showers could bring brief MVFR
conditions mainly to windward and mountain areas, especially
overnight and in the early morning hours.

With little change expected with the winds today, no change to the
AIRMETs. AIRMET Tango is in effect for moderate with isolated
severe turbulence over and immediately S through W of the island
mountains due to breezy trade winds, and reports yesterday of
severe turbulence.


&&

.MARINE...
High pressure will remain far north of the state this weekend
and help generate fresh to locally near gale trades across the
local waters. A Small Craft Advisory (SCA) is currently in effect
through tonight for most marine zones surrounding Maui and the Big
Island. Additional zones may need to be added to the SCA this
weekend as winds increase slightly. Trades then begin to weaken
by early next week as the aforementioned high drifts further
east.

Tropical Storm Iona continues to track to the west-northwest, far
southwest of the main Hawaiian Islands.

The current moderate to large, long period, south swell appears
to have peaked at the nearshore buoys, but is expected to hold
steady through the afternoon and continue to bring advisory level
surf to south facing shores. Thus, A High Surf Advisory remains
in effect for the south facing shores of all islands through 6 PM
HST. Expect a decline in swell energy tonight through this
weekend as the swell slowly fades. Another moderate, long period,
south swell should begin to build on Monday and help build surf
heights to near advisory levels once again.

East shore surf will remain elevated and choppy due to locally
strong trade winds through this weekend. This will be followed by
a decline early next week as trades weaken.

Flat summer conditions along north facing shores may be
interrupted late this weekend by a small long period northwest
swell from Typhoon Krosa, currently in the western Pacific.


&&

.FIRE WEATHER...
A gusty, stable, and rather dry trade wind flow will remain in
place through today, and likely into Saturday. Critical fire
weather conditions, with winds of 20 mph or more and daytime
relative humidity of 35 to 45 percent, is expected to persist over
leeward areas this afternoon, and possibly into Saturday. A
strong inversion based around 6,000 feet will ensure that higher
elevations of the Big Island and Haleakala on Maui experience very
low relative humidity. Winds will decline Sunday into Tuesday,
lowering fire weather concerns.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 6 PM HST this evening for Niihau-Kauai
South-Kauai Southwest-East Honolulu-Honolulu Metro-Ewa Plain-
Waianae Coast-Oahu North Shore-Central Oahu-Waianae Mountains-
Molokai North-Molokai West-Molokai Leeward South-Lanai Windward-
Lanai Leeward-Lanai South-Lanai Mauka-Kahoolawe-Maui Leeward
West-Maui Central Valley North-Maui Central Valley South-South
Maui/Upcountry-South Haleakala-Big Island South-Big Island
Southeast-Kohala-Big Island Interior.

High Surf Advisory until 6 AM HST Saturday for Niihau-Kauai
Leeward-Waianae Coast-Kahoolawe-Maui Leeward West-Kona-Kauai
South-East Honolulu-Honolulu Metro-Ewa Plain-Molokai Southeast-
Molokai Leeward South-Lanai Leeward-Lanai South-Maui Central
Valley South-Kipahulu-South Maui/Upcountry-South Haleakala-Big
Island South-Big Island Southeast.

Wind Advisory until 6 PM HST this evening for Lanai Mauka-
Kahoolawe-Kohala-Lanai Windward-Lanai Leeward-Maui Central
Valley North-Maui Central Valley South-Big Island South-Big
Island Southeast-Big Island North.

Small Craft Advisory until 6 AM HST Saturday for Kaiwi Channel-
Maui County Windward Waters-Maalaea Bay-Pailolo Channel-
Alenuihaha Channel-Big Island Windward Waters-Big Island Leeward
Waters-Big Island Southeast Waters.


&&

$$


DISCUSSION...M Ballard
AVIATION...M Ballard
MARINE...Thomas
FIRE WEATHER...M Ballard