Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 142010 CCA
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
1000 AM HST Thu Mar 14 2024

.SYNOPSIS...
A cool and dry air mass will soon move over the islands from the
north as a cold front moves through. In the short term, clouds and a
few showers associated with the dissipating front will blanket
windward areas, gradually diminishing through Friday, except over
windward Big Island. Light to moderate trade winds will favor a
northeast direction through the weekend, delivering limited windward
rainfall.

&&

.DISCUSSION...
A cool and dry air mass is poised to move over the islands from the
N in the next 12 to 24 hours, with dew points lowering about 10
degrees F. In the meantime, layered low- and mid-level clouds
associated with the dissipating front are draped over the islands
from Kauai to Maui, with a few light to moderate showers, mainly
over windward areas. Nearly clear skies currently prevail over the
Big Island. Moisture associated with this frontal boundary will move
slowly S to the Big Island through Friday. Drying and clearing will
occur over most areas as this occurs, while windward Big Island
becomes mostly cloudy, with periods of rain.

A relatively weak and slow-moving high pressure cell NW of the
islands will support light to moderate N winds today, with winds
veering to the NE Friday and Saturday. The high will weaken slightly
as it passes N of the islands Sunday and Monday, with light to
moderate ENE trade winds anticipated. Trade winds will prevail next
week, but a new high building NW of the islands around midweek will
turn trades back to the NE once again. Mostly dry and stable
conditions will prevail through the weekend, with just a few light
windward showers possible. A mid-level trough and its attendant
pocket of destabilizing cold air will move over the islands from
Tuesday through Friday next week. With PWAT being lower than normal
and a dry air mass remaining in place, just a slight increase in
showers is anticipated, except when moisture associated with a weak
front moves through the area Tuesday night/Wednesday, when there
could be an increase in windward showers.

&&

.AVIATION...
Northwest winds behind a weak cold front will spread bands of low
topped clouds and weak showers across all the smaller islands today.
Conditions will spread slowly eastward, reaching north and northwest
slopes of the Big Island by late afternoon and persisting overnight.

AIRMET Sierra is currently in effect for occasional mountain
obscuration for Kauai, Oahu, Maui, Molokai, and Lanai. Conditions
are expected to end by noon, but may redevelop overnight.

&&

.MARINE...
A weakening cold front will push down the island chain today and
tonight, with moderate to fresh northerly winds developing across
the waters. Winds will shift northeast at moderate to fresh levels
Friday as a weak high builds northwest of the state. Winds will ease
into the light to moderate range and shift to a more typical east-
northeasterly trade wind direction over the weekend into early next
week as the weak high passes by to the north of the state. Although
winds are expected to remain mostly below Small Craft Advisory (SCA)
thresholds through early next week, brief accelerations within the
windier channels are likely tonight as the front moves through.
Elevated seas will also impact portions of the marine area as a
large northwest swell moves through today through Friday night.
Therefore, the SCA that is currently in effect will likely need to
be expanded to include additional zones later today due to a
combination of winds and seas.

A long period, large northwest swell will be moving through the
islands today, with significant increases expected across exposed
north and west facing shores today with forerunners already reaching
north facing shores of the smaller islands. This swell will rapidly
build from northwest to southeast down the island chain this
morning, bringing warning level surf to north and west facing shores
of the smaller islands through Friday. Surf may reach advisory
levels along the west facing shores of the Big Island late tonight
through Friday night as well. This large swell will decline Friday
night and Saturday. A reinforcing northwest swell should arrive
Saturday night, keeping some moderate sized surf in place along
north and west facing shores through early next week. Another long
period northwest swell reinforcement may push surf up to advisory
levels Wednesday.

South shore surf will remain tiny through Saturday. A south swell
arriving Sunday should produce a slight increase in the surf that is
expected to persist through Monday. East shore surf will also remain
small through early next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Warning until 6 PM HST Friday 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.

Small Craft Advisory until 6 PM HST Friday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters.

&&

$$

DISCUSSION...Birchard
AVIATION...Bedal
MARINE...Vaughan


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