907
FXHW60 PHFO 130132
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
332 PM HST Sun Jan 12 2025

.SYNOPSIS...
Moderate to locally breezy trades will prevail through tonight,
before trending down through mid-week as a decaying front passes
by to the north and a stronger front approaches the area. Showers
will mainly focus over windward and mauka areas during this time.
A cold front could bring more widespread rainfall Thursday night
and Friday, with a slight chance for a few thunderstorms. A more
typical trade wind pattern is expected next weekend.

&&

.DISCUSSION...
Latest satellite and radar imagery still has an upper-level cutoff
low to the south of the Big Island helping to provide some instability
upstream of the state. This is helping to enhance showers as they
develop upstream of the islands and move into windward areas of the
islands. Moderate to locally breezy trade winds will remain in the
forecast through tonight, before gradually diminishing during the
first half of the week due to a weak front passing north of the state,
weakening the high to our northeast. Clouds and showers will remain
focused along windward and mauka regions. The eastern half of the
state will still have a good chance for enhanced tradewind showers
as the upper low slowly weakens and shifts northeastward tonight
through Monday. Mid-level ridging will build over the state as the
upper low exits the area to the east, creating a drier and more stable
tradewind weather pattern by Tuesday.

A strong cold front approaching the state midweek will cause the
winds to shift out of the southeast and weaken on Wednesday, becoming
light and variable Wednesday night through much of Thursday. This
will allow for sea and land breezes to develop, with showers favoring
island interiors each afternoon. The front is expected to quickly
sweep across the state during the second half the next week. Depending
on the strength and progression of the cold front through the islands
Thursday night and Friday, we could see more widespread rain affect
the islands, with some heavier showers and even a few thunderstorms
not out of the question. In the wake of the front, we will transition
back into a typical trade wind regime through next weekend.

&&

.AVIATION...
Locally breezy trade winds are expected to ease a bit tonight and
Monday as an approaching front weakens the ridging north of the
islands. Meanwhile, an upper low just southwest of the island
chain could continue to produce moderate to isolated severe upper
level turbulence this evening and tonight from Maui to the Big
Island, though this area will move further east away from the
islands by Monday as the upper low weakens and progresses eastward.

Showers embedded within the trades will generally favor north
through east sections of the islands throughout the forecast
period. Periods of MVFR ceilings and visibilities will be possible
for windward locations, with VFR flight conditions prevailing
elsewhere.

AIRMET Sierra continues for tempo mountain obscuration along
windward sections of the smaller islands this afternoon. Additionally,
AIRMET Tango remains in effect for moderate low-level turbulence
downwind of island terrain due to the breezy trade winds, but this
AIRMET will likely be cancelled later this afternoon or this
evening as trades ease. Finally, AIRMET Tango also remains in
effect for moderate to isolated severe upper level turbulence from
Maui to the Big Island, and will likely be needed until early
Monday morning.

&&

.MARINE...
The Small Craft Advisory (SCA) for moderate to locally strong
trade winds has been cancelled. Wind speeds have fallen below
advisory criteria and will further weaken overnight.

High pressure over the northeast Pacific will continue to weaken.
A weak front will pass just north of the state Tuesday night. A
second cold front will move into the western waters Thursday
night. In response, trade winds will weaken through Wednesday. On
Thursday, winds will further weaken and shift to the north. By
late Friday, the front should exit the area, and light trade winds
return.

The current moderate northwest (330) swell has peaked and will
fade overnight. On Monday, a new larger long-period northwest
(320) will quickly build in to take its place. This second swell
is expected to peak Monday afternoon or evening then gradually
decline through midweek. A High Surf Advisory has been issued for
north and west facing shores of Niihau, Kauai, Oahu, and Molokai,
as well as north facing shores of Maui. The advisory goes into
effect early Monday and continues through Tuesday afternoon.

Towards the end of the week, an even larger northwest swell will
build. This third and largest swell could bring warning level surf
to most north and west facing shores on Friday and Saturday.

Surf along east facing shores will hold relatively steady through
tomorrow then lower a bit Tuesday and Wednesday as the trade winds
ease. East shore surf looks to become very small Wednesday and
Thursday as the trades become disrupted, with a north swell
potentially giving surf a boost to exposed shorelines on Friday.

South shore surf will remain very small through the middle of the
week. An out of season long-period south swell may move through
the islands at the end of the week, bringing a sizable boost to
south shore surf.

&&

.FIRE WEATHER...
No critical fire weather conditions expected through the forecast
period as low-level moisture remains sufficient, with wind speeds
remaining below critical thresholds. In addition, a front could
bring a period of more widespread rainfall to the islands around
the end of the week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory from 6 AM Monday to 6 PM HST Tuesday for
Niihau-Kauai Leeward-Waianae Coast-Oahu North Shore-Maui
Windward West-Kauai North-Molokai Windward-Molokai North-Molokai
West-Maui Central Valley North-Windward Haleakala.

&&

$$

DISCUSSION/FIRE WEATHER...TS
AVIATION...Vaughan
MARINE...Bedal