Lahaina, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

200
FXHW60 PHFO 240643
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
843 PM HST Mon Dec 23 2024

.SYNOPSIS...
A high pressure system passing north of the Hawaiian Islands will
keep moderate to breezy trade winds in the forecast through
Tuesday. Winds will veer from the east southeast direction and
weaken to light to moderate levels from Wednesday through Friday.
A shallow cold front and upper level disturbance are forecast to
move into the islands this weekend. Expect another round of
moderate to breezy trade winds as a high builds in behind the
dissipating front, enhancing trade wind showers over the typical
windward and mountain areas.

&&

.DISCUSSION...
The latest satellite imagery this evening shows a long band of
clouds associated with a dissipating shallow cold front stalled
out just north of the state. Moderate to breezy trade winds may
bring some of these cloud bands and a few showers into the
western islands of Kauai and Oahu into Tuesday. Local radar
imagery shows isolated light shower activity.

Looking at the wind forecast for this week, we see a high
pressure system located north of the state drifting eastward.
This system will continue to produce moderate to breezy trade
winds over the islands into early Wednesday morning, which will
continue to blow from the east-northeast to east direction. This
high center will then drift into the East Pacific, away from the
islands, as a cold front approaches the state from the northwest.
Wind speeds will decrease and shift directions out of the east to
southeast direction from Wednesday afternoon through Friday.
Lighter large scale winds will allow local scale onshore sea
breezes to expand in coverage over each island during this time
period. Another migratory high passing north of the state along
with a shallow cold front moving into and dissipating over the
islands this weekend will bring another round of moderate to
breezy trade winds to the Hawaii region from Saturday into early
next week.

Weather wise a stable ridge aloft will keep low temperature
inversion heights in place in through Friday. Then the weather
pattern shifts as a dissipating cold front will potentially move
into and dissipate over the western islands this weekend. An
upper level trough moving in with this front will likely enhance
trade wind showers on Saturday and Sunday. Global models continue
to suggest this trough will deepen into an upper level low and
become stationary just east of the Hawaiian Islands by Sunday. If
this upper level low position verifies, then the lift from this
upper level disturbance will inject instability into the low level
cloud field upstream of the islands; briefly enhancing trade wind
showers. The highest shower coverage in this scenario would favor
windward and mountain areas in the overnight to early morning
time period.

&&

.AVIATION...
Moderate to locally breezy trades will continue through Tuesday,
although winds will be a bit lighter than what was seen today.
Light showers will favor windward slopes and coasts, with brief
MVFR cigs/vsbys possible. VFR conditions will prevail in leeward
areas, with the exception of PHNY which will likely see some MVFR
cigs during the daytime heating hours.

AIRMET Tango remains in effect for moderate low level turbulence
over and downwind of terrain of all islands. This AIRMET will
likely hold through the night with improving conditions expected
by Tuesday afternoon.

&&

.MARINE...
Fresh to strong easterly trades will persist through tonight as a
ridge builds north of the area. A Small Craft Advisory (SCA)
remains in effect for all Hawaiian waters either due to strong
trades or for combined seas exceeding 10 feet. Trades will
gradually ease and shift southeasterly Tuesday before becoming
light and variable for the western half of the state by Wednesday
night into Friday. Southeast winds for the eastern half of the
state will become gentle to moderate Thursday into Friday.

The current northwest swell (310-330) continues to trend down at the
offshore and near shore buoys and is becoming more in line with
model guidance. A High Surf Advisory (HSA) remains in effect along
north and west facing shores through 6 pm HST Tuesday, but surf
heights may drop below thresholds earlier than that. The next
large, long period northwest swell (310 degrees) is expected to
fill in late Wednesday night, peak Thursday before gradually
trending down Friday into the weekend. This second swell is
excepted to produce warning- level surf along north and west
facing shores, albeit smaller than the event this past weekend.
Surf along east facing shores will briefly become rough and choppy
tonight and Tuesday as trade wind swell has picked up. A downward
trend is expected during the second half of the week as winds
weaken locally and upstream.

&&

.FIRE WEATHER...
No critical fire weather conditions are expected for the next
seven days. Mostly dry weather are forecast across the state with
limited shower activity as the dry spell continues through Friday.
Shower trends increase starting Friday night with trade wind
showers.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 PM HST Tuesday for Niihau-Kauai
Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kona-
Kohala-Kauai North-Molokai Windward-Molokai North-Molokai West-
Maui Central Valley North-Windward Haleakala-Big Island East-Big
Island North.

Small Craft Advisory until 6 PM HST Tuesday for all Hawaiian
waters-

&&

$$

DISCUSSION...Bohlin
AVIATION...Jeslema
MARINE...Almanza
FIRE WEATHER...Bohlin