Captain Cook, Hawaii Weather Forecast Discussion

513
FXHW60 PHFO 140143
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
343 PM HST Sat Sep 13 2025
.SYNOPSIS...
High pressure centered northeast of Hawaii will drive moderate to
fresh trade winds with dry and stable weather into next week.
An upper trough will drift through the islands from Tuesday to
Thursday possibly increasing showers.
&&
.DISCUSSION...
High pressure centered northeast of Hawaii will drive moderate to
fresh trade winds with dry and stable weather into next week.
Visible satellite shows cloud build ups over lower slopes on the
Big Island, and a few cirrus clouds passing over the state. Otherwise
conditions are mostly sunny to partly cloudy with virtually no
precipitation observed on radar. The overall pattern will change
little through Monday, with the best chance for rainfall and cloud
cover over the windward slopes, but accumulations will be light.
A tropical wave will pass south of the state Tuesday through
Thursday. Upper level troughing will set up over the state around
the same time may act to enhance showers moving in on both the
trade wind flow and the far northern periphery of the wave. Clouds
and showers will likely increase during this time frame focusing
over windward and mauka areas. The upper trough may become an
upper low and deepen next weekend possibly further enhancing
rainfall.
&&
.AVIATION...
Moderate to locally breezy trade winds will persist for the next
few days as high pressure remains situated northeast of the state.
Brief passing showers will favor windward and mountain areas in
the overnight to early morning hours. VFR conditions will prevail
outside of showers.
No AIRMETs are in effect.
&&
.MARINE...
Little change in the forecast with the afternoon package.
High pressure will remain nearly stationary north of the islands
into Monday. Meanwhile a low pressure system to the southeast of
the islands will move to the west. The resultant pressure gradient
over the islands will maintain the moderate to locally strong
trades through Sunday. Heading into Sunday night and Monday, winds
will weaken as the high to the north is eroded by a cold front
moving west to east. A Small Craft Advisory (SCA) remains in
effect for the windier waters near Maui County and the Big Island.
This SCA is in place through Sunday afternoon, with winds expected
to fall below SCA levels Sunday night. High pressure building
north of the islands behind the above mentioned cold front, will
allow trade winds to increase again Tuesday night into Wednesday,
when another SCA may be needed.
No advisory level swell are expected this week. The current
small, medium period south swell will continue to fall over the
remaining daylight hours today, with a small longer period
reinforcement swell expected to arrive tonight. That will hold the
surf along south facing shores around waist high through Sunday.
The current north swell will continue to decline through Sunday.
Another small, medium period north swell is expected to arrive
Thursday, causing a small bump in surf late in the week. Typical
short period wind wave chop will occur along east-facing shores
with the moderate to locally strong trades this weekend.
&&
.FIRE WEATHER...
Humidity levels will remain dry into next week with increasing
humidity and shower trends from Tuesday into Wednesday as a weak
low level trough drifts from east to west across the island chain.
Wind speeds will likely remain below critical fire weather
thresholds for the next seven days. Temperature inversion heights
near the Big Island and Maui will range from 5,500 to 6,500 feet
through the weekend.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.
&&
$$
DISCUSSION...Foster
AVIATION...Farris
MARINE...M Ballard
FIRE WEATHER...Foster

NWS HFO Office Area Forecast Discussion