Kahului, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

547
FXHW60 PHFO 020630
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
830 PM HST Tue Apr 1 2025

.SYNOPSIS...

Rain chances will steadily increase through the week especially
over the western half of the state as a frontal boundary moves
over Kauai and stalls near Oahu Thursday into Friday. Breezy to
locally strong trade winds should return on Friday with a showery
trade wind pattern expected through the weekend. Once again, the
trade wind showers should be most frequent over the western half
of the state.


&&

.DISCUSSION...

Forecast remains on track and no changes have been made for the
evening update. Light to moderate south to southeasterly winds
will weaken some Wednesday but the wind direction will continue to
remain out of the south or southeast. With the ongoing eruption
of Kilauea and the southeasterly winds over the Big Island, we
have had reports of Pele`s hair falling onto Highway 11. The
southeasterly winds should weaken this evening with land breezes
developing overnight tonight. Southeasterly winds will likely
develop during the day on Wednesday and with the general
southeasterly flow, more widespread vog will be possible on
Wednesday.

A frontal boundary currently located west of Kauai will slowly
shift eastward over the next few days. Satellite imagery this
evening continues to show a broad NE to SW oriented line of
showers and thunderstorms roughly 180 miles west of Kauai. This
line of heavier showers is expected to slowly move east and
gradually weaken as it approaches Kauai Wednesday into Thursday.
Starting Wednesday as the frontal boundary nears Kauai, we could
begin to see some heavier showers especially during the afternoon
over the western half of the state. There are still quite a bit of
uncertainty for precipitation amounts on Wednesday due to the
uncertainty in the location of the frontal boundary. GFS ensembles
brings the frontal boundary very close to Kauai, while the EC and
Canadian ensemble members keeps the bulk of the moisture slightly
further west of Kauai. Thus, the precipitation amounts still
remain uncertain for Wednesday over Kauai and Oahu, but off and on
scattered showers should be expected. For rest of the state,
isolated to scattered showers will be possible on Wednesday with
mostly light rainfall amounts.

On Thursday, there is better agreement with global models with the
frontal boundary reaching Kauai. This should allow for some
moderate to locally heavy showers over Kauai and Oahu. With
generally light winds on Thursday, any showers will be slow moving
and we could see some flooding concerns especially over north
Kauai. The frontal boundary is expected to weaken and stall
somewhere around Kauai or Oahu on Friday. Breezy to locally strong
trade winds will also return on Friday with a showery trade wind
pattern expected across the state over the weekend. The greatest
moisture will once again continue to be across the western half of
the state, especially Kauai. So overall, showery weather should be
expected over Kauai and possibly Oahu from Thursday through the
weekend. Passing showers should also increase for the eastern half
of the state once the trade winds return.


&&

.AVIATION...

Moderate southerly winds will continue tonight over the western
half of the state as a cold front approaches from the northwest.
Expect an uptick in shower activity across Kauai and Oahu as
moisture streams in from the south ahead of the front, with
periods of MVFR likely with the heavier showers.

Otherwise, the eastern half of the state will see moderate to
locally breezy southeasterly winds continue into Wednesday, with
localized sea breezes in sheltered areas. Conditions should remain
mainly VFR.

No AIRMETs are currently in effect, but AIRMET Sierra for tempo
mountain obscuration may be needed for Kauai and Oahu as showers
become more widespread.

All areas will continue to see some Vog due to the ongoing
eruption of Kilauea. However, the Vog is not expected to impact
visibilities enough to warrant a mention in any TAF.


&&

.MARINE...
A cold front, slowly approaching the islands from the west, will
maintain breezy southeasterly flow across the eastern portion of
the state and light to moderate southerly flow elsewhere. A Small
Craft Advisory (SCA) remains in effect through Wednesday morning
for waters around the Big Island for local wind acceleration
around and along the parallel coastlines to the wind direction.
This advisory may need to be extended through Wednesday afternoon
as these winds gradually ease throughout the day. As the
aforementioned front moves across the smaller islands and
dissipates, moderate to locally strong northeast trades are
expected to develop this weekend and early next week.

A moderate north-northwest (330-350) swell is expected to arrive
on Friday and could produce advisory level surf. A large to extra
large, long period, north to north-north west (340-360) swell is
forecast to arrive this weekend and would likely produce warning
level surf along north facing shores with advisory level surf
across west and east facing shores. This swell, aside from being
hazardous to small craft, could generate harbor surges along north
facing bays and inlets.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Wednesday for Big Island
Windward Waters-Big Island Leeward Waters.


&&

$$


DISCUSSION...Almanza
AVIATION...Walsh
MARINE...Thomas