FXHW60 PHFO 281922
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
922 AM HST Sat Sep 28 2024

.SYNOPSIS...

Trade winds will strengthen slightly to become moderate to locally
breezy today and then decrease slightly to moderate levels from
Sunday into early next week. Showers will favor windward and
mountain areas, especially in the overnight to early morning
hours. A slightly drier trade wind pattern is expected later today
through Monday, followed by subtle wetter trends from Monday night
into Wednesday.

&&

.DISCUSSION...

Radar and satellite are showing some low clouds and isolated to
scattered showers moving into windward and mauka areas on the
trades this morning, with a few showers sneaking around island
terrain and into leeward areas at times. This activity will wane
throughout the day as drier air filters in behind a weak low level
trough exiting west of the island chain, bringing more sunshine
and relatively drier conditions for the rest of today and
tomorrow.

Taking a look at the big picture, the mid level ridge overhead
will retreat further away to the NE as a deep mid/upper level
trough sweeps into the north central Pacific (and stays far north
of Hawaii) next week. At the surface, a ridge of high pressure
will be disturbed by a series of lows and fronts of varying
magnitudes marching across the far northern Pacific, generally
maintaining moderate trades across the main Hawaiian Islands
through much of next week. There will be only subtle changes in
the trade wind speeds over the next couple of days in response to
these fluctuations in the surface ridge. As such, today is
expected to be locally breezy as the ridge builds slightly, then
a cold front approaching from the northwest (that will stay well
north of the state) will bring a slight decline in trade wind
speeds Sunday and Monday before they strengthen to moderate levels
heading into the rest of the week.

The aforementioned drier trade wind pattern will last into
Monday. For the rest of the week, batches of low level moisture
will filter across the state on the moderate trades and bring
brief upticks in windward and mauka showers. As is typical
in a trade wind pattern, a slight uptick in shower activity can
be expected overnight into the early morning hours through the
forecast period.

&&

.AVIATION...

Stable, moderate trades deliver limited showers windward and
mauka through the forecast period. Brief MVFR possible within any
heavier showers, otherwise VFR prevails.

No AIRMETs in effect.

&&

.MARINE...
A ridge of high pressure north of the state will maintain
moderate to locally strong trades through tonight. A Small Craft
Advisory remains in effect for the windier waters around Maui
County and the Big Island through tonight. A front passing far
north of the state over the next few days will cause the ridge to
shift closer to the state and will result in the trades weakening
to gentle to moderate speeds through Monday. As the front
dissipates, the ridge will shift slightly further north and
should increase the trade winds to moderate to locally fresh
speeds by middle of next week.

A small, medium period north-northwest swell will fill in today and
peak tonight then gradually decline on Sunday. This swell should
gradually veer towards the north as it declines. A similar or
slightly larger, medium period northwest should arrive on Tuesday
and peak late Tuesday, then shift directions out of the north on
Wednesday as it declines.

A series of small long-period southwest swell should provide some
small but inconsistent waves along south facing shores the next few
days. A slightly larger south-southwest swell should fill in next
Tuesday and hold through Wednesday then decline through the rest
of the work week. A storm force low currently passing south of New
Zealand will lift northward with a large fetch of gales passing
east of New Zealand Sunday into Monday. This should produce a
moderate south-southwest swell with long-period forerunners
filling in as early as next Saturday (Oct 4th) and likely peaking
on Sunday (Oct 5th) with swell heights of around 3 to 4 ft.

East shore surf will remain small through most of next week,
although select spots with more northerly exposure could see some
of the north swells.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Sunday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

&&

$$

DISCUSSION...Farris
AVIATION...JVC
MARINE...Kino