Haiku-Pauwela, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

986
FXHW60 PHFO 171335
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
335 AM HST Sun Aug 17 2025

.SYNOPSIS...
Moderate to locally breezy trades persist through the morning
with passing windward and mauka showers. Later today, a low-level
trough associated with the remnants of former Tropical Cyclone Ivo
will propagate across the islands, bringing increased clouds and
shower activity predominately to the windward and mauka areas. By
midweek, another plume of moisture is expected to passing into
the region, again increasing clouds and showers. Otherwise, drier
and more stable conditions prevail through the remainder of the
week.


&&

.DISCUSSION...
Broad area of high pressure remains quasi-stationary north of the
islands, allowing moderate to locally breezy trades to prevail
with passing windward and mauka showers. Latest deterministic
model guidance of the GFS and ECMWF are in strong agreement
supporting a quick moving, low-level trough associated with the
remnants of former Tropical Cyclone Ivo to propagate toward Maui
County later this afternoon before shimmying northwestward.

As the trough approaches, relative humidity levels will
increase slightly today into Monday as moisture associated with
the trough begins to filter onto the islands. Trades will weaken
briefly, maintaining light to moderate trades across the region.
The trough will also bring a slight increase in instability to the
region, allowing the inversion to lift around 8,000 to 9,000
feet. Expect an uptick in shower activity across windward Maui by
Sunday evening, with the moisture plume spreading westward into
Oahu and Kauai County Sunday night into Monday. Rainfall totals up
to 0.25 inches across windward and mauka areas of the smaller
islands with locally higher amounts possible within this fast
moving system.

By Tuesday, the aforementioned trough exits the region, with high
pressure quickly rebuilding in its wake, allowing moderate to
locally breezy trades return. However, latest guidance now
showcases another moisture plume propagating into the vicinity
Wednesday, which may enhance cloud coverage and shower activity to
windward and mauka areas again midweek. Otherwise, expect
predominately dry and stable conditions to return for the latter
half of the forecast period, with typical summertime conditions
yielding limited clouds and showers across the state under
moderate to breezy trades.


&&

.AVIATION...
Moderate to locally breezy trades persist through the forecast
period. Brief periods of MVFR conditions possible in low ceilings
and showers, predominately windward and mauka areas with limited
leeward spillover. Otherwise, VFR conditions prevail

No AIRMETs in effect at this time, however, as a low-level trough
moves into the region, AIRMET Sierra may become necessary for
mountain obscuration due to incoming shower activity.


&&

.MARINE...
Persistent ridging north of the state will lead to a rather stable
weather pattern with typical fresh to locally strong trades
through a majority of the of the forecast period. The Small Craft
Advisory (SCA) will remain in effect from the Kaiwi Channel
eastward through this afternoon. Trades are forecast to weaken
just below SCA thresholds tonight through early Monday morning as
a weak trough from the remnants of Tropical Cyclone Ivo pass from
east to west over the smaller islands. Moderate to locally strong
trades will restrengthen Monday afternoon and maintain strength
through the remainder of the week.

A 2 to 3 foot, medium period south southwest (180-200) swell will
hold today and generate waist to chest high surf, near seasonal
norms. A series of very similar small, medium period south swells
will pass through the local waters through the work week. These
swells will help to maintain seasonal surf heights along the
south- facing shores, well below advisory thresholds.

Expect chop along east facing shores to remain elevated today,
then lower tonight into Monday morning as trades weaken slightly.
Fresh trades will once again bring elevated choppy conditions to
east facing shores Monday afternoon through mid- week. Flat to
tiny surf will persist along north facing shores through the
forecast period.


&&

.FIRE WEATHER...
Conditions should remain below critical fire weather thresholds
into early next week. A low-level trough associated with the
remnants of former Tropical Cyclone Ivo will move across the
state later today through Monday, bringing an increase in
humidity and shower activity. By midweek, another plume of
moisture is expected in the vicinity of the islands, which may
increase shower activity again on Wednesday. Otherwise, expect
dry and stable conditions for the latter half of the week as high
pressure rebuilds across the islands.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST this evening for Kaiwi
Channel-Maui County Windward Waters-Maui County Leeward Waters-
Maalaea Bay-Pailolo Channel-Alenuihaha Channel-Big Island
Windward Waters-Big Island Leeward Waters-Big Island Southeast
Waters.


&&

$$


DISCUSSION...Pierce
AVIATION...Pierce
MARINE...Thomas
FIRE WEATHER...Pierce