High Wind Warning 6, NWS Honolulu, HI

Area Forecast Discussion
National Weather Service Honolulu HI
903 PM HST Thu Feb 1 2024

.SYNOPSIS...
The weather impacts this weekend into early next week are wind
driven with strengthening northerly winds on Friday behind a
rapidly moving cold front. These increasing northerly winds turn
into windy northeast to east trade winds from early Saturday
morning through the first half of next week affecting all Hawaiian
Islands. Strong trades gradually drop down to moderate to locally
breezy levels by next week Thursday. Showers will continue
statewide through much of Friday with decreasing rainfall trends
developing after the cold front passes through each island. Trade
wind showers return starting late Saturday to Sunday mainly over
windward and mountain areas with drier conditions forecast over
leeward areas.

&&

.DISCUSSION...
Starting with the infra-red satellite imagery this evening, we see
a band of clouds associated with a weak surface trough over the
central islands. These clouds are producing light to moderate
showers over Oahu and the islands in Maui County. Farther
northwest of Kauai, a cold front approaches the state from the
northwest. This cold front will sweep into the western islands
early Friday morning, expect increasing clouds and showers as it
passes and moves eastward across the state. The main weather
impact with this passing front will be in the strengthening
northerly winds as a high pressure system builds in behind the
passing frontal trough.

An extended period of strong wind impacts are expected after the
cold front passes through the state on Friday. Northerly winds
will strengthen over each island on Friday. These winds will
quickly reach breezy to windy levels and the directions will veer
more northeasterly by early Saturday morning. These very strong
trade winds will continue and shift to easterlies from Sunday
through Monday as a strong high pressure system builds in north of
the island chain. Wind advisories are likely this weekend as
strong gusty winds may bring nuisance level impacts such as
flying debris, broken tree branches, and possible power outages.
These advisory level winds may continue into Monday.

Strong winds will gradually decrease each day from Tuesday onward,
where the easterly trade winds blow at more moderate to locally
breezy levels by Thursday. Another low pressure system will move
into the Central Pacific by the end of next week, with decreasing
southeasterly winds in the forecast as the trailing cold front
breaks down the high pressure ridge north of the islands.

&&

.AVIATION...
Bands of clouds and showers ahead of a new approaching cold front
will traverse the smaller island tonight then spread across the
Big Island on Friday. Light and variable winds are expected to
shift to the north and increase in intensity once the front
arrives Friday afternoon.

Locally heavy downpours possible in showers. Occasional MVFR
ceilings and visibilities are to be expected in passing showers.
AIRMET Sierra for mountain obscuration is currently in effect for
Oahu, Molokai, and Lanai, and will likely need to be expanded to
include Maui later tonight.

AIRMET Tango for low level turbulence to the south and west of
island terrain may be needed just beyond the forecast period when
north winds increase behind the front.

&&

.MARINE...
High pressure to the distant west-northwest will build eastward in
the vicinity of 30N, pushing a cold front southeastward through
the island chain Friday and Friday night. North winds gradually
increase tonight and Friday, with SCA level winds expected across
all waters by late Friday afternoon. The high will strengthen and
shift northeastward Saturday night, before settling southward and
closer to the islands Sunday through the middle of next week.
Strong to near Gale force winds are expected across the during
this time, with strongest winds in the windier waters around Maui
and the Big Island, where Gale force winds are possible. A Gale
Watch remains in effect for these areas Saturday through Sunday.
This Gale Watch may need to be moved forward to begin Friday
evening based on the new high resolution model guidance.
A Small Craft Advisory is now in effect for windward waters
tonight through 6 AM Saturday, with most other zones joining the
advisory Friday morning. This SCA will assuredly need to be
extended in time with the morning forecast package.

A pair of overlapping north to north-northeast swells have come in
higher than predicted at nearshore buoys this evening, and as a
result a High Surf Advisory is now in effect for north and east
facing shores of most islands tonight through Sunday. move into
the Hawaii region through this weekend. Given the strong trade
winds and the north-northeast swell direction, impacts are also
likely from harbor surges exposed northern harbors, including
harbor surges at Hilo and Kahului. See the Marine Weather
Statement for additional details.

Advisory level surf may linger through Monday along north and east
facing shores, as while the north-northeast swell declines, a new
large northwest swell will build and easterly trade wind swell
will increase. North shore surf should lower below advisory
thresholds by Tuesday, with east shore surf likely holding at
advisory levels through Wednesday. Surf should lower below
advisory levels along east facing shores by next Thursday as the
trades begin to ease.

South shore surf will remain small through early next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory from 6 AM Friday to 6 PM HST Sunday for
north and east facing shores of most Hawaiian Islands.

Small Craft Advisory until 6 AM HST Saturday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Kaiwi Channel-Maui County Windward Waters-
Alenuihaha Channel-Big Island Windward Waters.

Small Craft Advisory from 6 AM Friday to 6 AM HST Saturday for
Oahu Leeward Waters-Maui County Leeward Waters-Big Island
Leeward Waters-Big Island Southeast Waters.

Gale Watch from Saturday morning through Sunday afternoon for
Maalaea Bay-Pailolo Channel-Alenuihaha Channel-Big Island
Southeast Waters.

&&

DISCUSSION...Bohlin
AVIATION...Bedal
MARINE...Jelsema