Lahaina, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

138
FXHW60 PHFO 031328
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
328 AM HST Tue Dec 3 2024

.SYNOPSIS...

Relatively dry and stable conditions will persist through
Wednesday with light winds that will allow for sea breezes each
day and land breezes overnight. A front will move through Kauai on
Thursday then dissipate over the central portion of the state on
Friday. Chances of rain will increase ahead of and along the
frontal boundary with moderate to locally breezy northeast winds
filling in behind it.

&&

.DISCUSSION...

A dry and stable air mass will remain in place through today due
to a ridge of high pressure over the state. Winds will be light
and variable with a background southerly flow. Winds should be
light enough for day time sea breezes and night time land breezes.
Day time sea breezes will lead to afternoon clouds over interior
and mountain areas with a few light showers possible. A slightly
stronger southeast flow is expected to fill in from the south
today into Wednesday, ahead of the front that should gradually
increase moisture in the area tonight into Wednesday.

Starting Wednesday, a front will begin to approach the state from
the northwest. Southerly wind flow will strengthen around the
western end of the state, increasing chances of showers. By
Thursday, the front is expected to be over or through Kauai with
some prefrontal showers increasing over Oahu and possibly parts of
Maui County. The front is expected to eventually stall out and
dissipate near the central portion of the state Friday. Overall
the front does not look very impressive, but it could bring some
light to moderate rainfall to some much needed locations on the
leeward side. Some locally heavy rainfall will be possible late
Thursday into Friday, in the area where the frontal boundary
stalls.

Moderate to locally breezy trades should briefly return over the
western half of the state on Friday as a weak high develops
northwest of the state. Trades will be short- lived as the high
quickly shifts east as another front passes north of the state.
This will put the western end of the state in a light wind flow
patter while gentle easterly winds linger over the eastern end.
Confidence in the weather forecast over the weekend remains low
with most of the ensemble members showing some type of upper level
trough pushing through the state. Stay tuned for more details.

&&

.AVIATION...

A ridge of high pressure sitting over the state will allow for
light and variable winds causing sea/land breezes
every day/night through at least midweek. SHRA and isol low cigs
will be possible but VFR conds should prevail.

No AIRMETs currently in effect and none are anticipated.

&&

.MARINE...
An E-W oriented surface ridge extending over the islands from the
E is supporting gentle winds statewide that are out of the E-SE
over Big Island waters, and from the S-SW over Kauai and Oahu
waters. Little overall change in the ridge`s position is expected
through Wednesday. A low passing N of the islands late Wednesday
and Thursday will force the ridge eastward, with a tightening
low-level gradient supporting fresh to locally strong S to SW
winds statewide as an associated front approaches from the NW.
Fairly high confidence in the front moving over Kauai and Oahu
from late Thursday into Friday, likely stalling on Friday over
the central portion of the island chain. Winds and/or seas will
likely reach Small Craft Advisory criteria in at least some of the
waters Thursday and Friday.

As the front dissipates, locally fresh post-frontal N winds will
gradually ease and veer to the NE Thursday night into Friday.
Wind speeds will quickly diminish into Saturday, when a period of
light and variable winds is expected. Light NE winds on Sunday are
expected to give way to increasing trade wind flow in the longer
term.

Fetches of near-gale to gale-force winds associated with fast-
moving low pressure systems passing well N of the area will send
NW swells of varying sizes and periods toward the islands this
week. Although most of the swell energy will be in the shorter-
period 12-14 second bands, resultant surf is expected to be near
or above High Surf Advisory (HSA) levels along exposed N and W
facing shores at times.

Wave/swell heights at NDBC buoys 51001/51101 NW of Kauai have increased
overnight, where significant wave heights have reached as high as
11 feet. Although primarily associated with relatively short-
period (12 seconds) NW swell, longer period (14-17 second) bands
are seeing increased NW swell energy over the last several hours.
Resultant surf is expected to peak near High Surf Advisory (HSA)
levels later today, and a HSA is in effect for exposed shores.
Another NW swell Thursday into Friday will likely produce HSA-
level surf before a general diminishing trend in NW swell develops
by next weekend.

A long-period S swell will peak today, producing surf near
summertime averages along S facing shores, before gradually
diminishing through Thursday. Another similarly-sized long-period
S swell is expected by next weekend.

&&

.FIRE WEATHER...

Critical fire weather conditions are not expected through the rest
of the week and into the weekend. Daytime relative humidity
values may briefly approach critical levels this afternoon but
winds will remain light and preclude any fire weather concerns.
From Wednesday into the weekend, minimum relative humidity values
are expected to trend above critical levels due to increasing
moisture and showers as a front approaches and dissipates near the
central portion of the state.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory from noon today to 6 AM HST Wednesday for
north and west facing shores of Niihau Kauai Oahu Molokai and
north facing shores of Maui.


&&

$$


DISCUSSION...Almanza
AVIATION...Walsh
MARINE...Birchard