Mililani Mauka, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

001
FXHW60 PHFO 241334
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
334 AM HST Tue Dec 24 2024

.SYNOPSIS...
A high pressure system passing north of the Hawaiian Islands will
keep moderate to breezy trade winds in the forecast today. Winds
will veer from the east to southeast direction and weaken into
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 into early next week.

&&

.DISCUSSION...
The latest satellite imagery this morning continues to show 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 later today. Local
radar imagery shows only isolated light shower activity across the
state.

Looking at the wind forecast for this week, we see a high
pressure system located northeast of the state drifting eastward.
This system will continue to produce moderate to breezy easterly
trade winds over the islands through this afternoon. This high
center will slowly 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 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 near the Hawaiian Islands sometime early next
week. Forecast confidence on the precise location for this system
is low at this time. If this upper level low position does in fact
set up near the islands, then the lift from this upper level
disturbance will inject instability into the low level cloud field
upstream of the island chain; briefly enhancing trade wind
shower activity. The highest shower coverage in this scenario
would favor windward and mountain areas in the overnight to early
morning time period.

Long range operational model solutions continue to show various
solutions for an upper level low to develop and hover near the
islands early next week. The latest GFS and ECMWF ensemble
solutions keep the low center east of the Big Island. Still too
early to include much confidence in the forecast details for days
7 and 8. However, there may be a brief window, next week Monday or
Tuesday, where some ice and snow may develop over the Big Island
summits of Mauna Kea and Mauna Loa. Stay tuned.

&&

.AVIATION...
Moderate to locally breezy trades will continue today, although
winds will be a bit lighter than what was seen yesterday. The
trades will ease further tonight as they shift more east-
southeasterly resulting in more terrain blockage of the stronger
winds. 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. Conditions should
improve later today.

&&

.MARINE...
Fresh to strong easterly trades continue over the eastern half of
the state this morning. Winds have veered slightly out of the
southeast over the western half of the state and eased to moderate
to locally fresh. The Small Craft Advisory (SCA) has been scaled
back to windward Oahu waters and waters east of Oahu through this
afternoon due to the combination of strong winds and lingering
high seas. Winds and seas are expected to drop below SCA
thresholds tonight as winds continue to gradually ease and shift
out of the southeasterly. Winds are expected to become light and
variable for the western half of the state by Wednesday night into
Friday. East to southeast winds will persist over the eastern
half of the state and become gentle to moderate Thursday into
Friday.

The current northwest swell (310-330) continues to trend down at the
offshore and near shore buoys. The High Surf Advisory (HSA) for
north and west facing shores has been dropped this morning as the
swell continues to trend down at the local buoys. 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. This large swell will
also elevate seas to above SCA thresholds as the swell fills in
Wednesday night. Surf along east facing shores will briefly
become rough and choppy today 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...
Small Craft Advisory until 6 PM HST this evening for Oahu
Windward Waters-Kaiwi Channel-Maui County Windward Waters-Maui
County Leeward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha
Channel-Big Island Windward Waters-Big Island Leeward Waters-Big
Island Southeast Waters.

&&

$$

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