Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 221332
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
332 AM HST Fri Mar 22 2024

.SYNOPSIS...
Breezy northeast trade winds will become more easterly this
weekend through early next week. Drier air will fill in over the
weekend, providing limited clouds and showers windward and mauka.

&&

.DISCUSSION...
Satellite loop shows a broad anticyclonic circulation across the
central North Pacific this morning, marking a subtropical high.
The main Hawaiian Islands lie within a belt of northeasterly
trades along the southern flank of this circulation. Ragged bands
of patchy broken low clouds keep skies covered across windward
sections of Kauai and the Big Island, but the remaining islands
lie beneath scattered low clouds to clear skies. Overnight
soundings show a rather dry airmass, with PW ranging from 0.9 to
1.1 inches. Radar shows isolated to scattered light showers
beneath cloud cover across windward portions of Kauai and the Big
Island, with more showers noted across waters upwind from Oahu and
Molokai, but very little activity elsewhere.

Models show stronger winds shifting southward over the state
today as a band of moistures rides ahead. This will translate to
a slight increase in clouds and showers for Kauai and Oahu later
this morning and for the rest of the state through the course of
today. Breezy northeast trade winds will veer more easterly this
weekend as the high north of the state gradually strengthens and
tracks eastward. Given the dryness of our airmass, any clouds and
showers that form will be limited to windward and mauka areas.
Models show increased moisture early next week as an area of high
PW moves in from the south, raising values to around 1.5 inches
across the state by Tuesday. Upper troughing over the state could
increase shower coverage over windward areas, while breezy trade
winds persist.

&&

.AVIATION...
Breezy northeast trade winds will persist, with clouds and
showers favoring windward areas. The best windward shower coverage
is initially expected over the Big Island and the western end of
the state where a band of low-level moisture has settled southward
into the area. Similar conditions are anticipated over Maui
County later today through tonight as this band continues
southward.

AIRMET TANGO remains in effect for low-level turbulence over and
S thru W of mountains.

AIRMET SIERRA remains in effect for mountain obscuration due to
MVFR CIGs/VSBYs in SHRA for windward Big Island, Kauai, and Oahu.

&&

.MARINE...
Surface high pressure north of the state will gradually strengthen
and drift east through the weekend. This will result in nearshore
winds increasing to Small Craft Advisory (SCA) magnitudes across
more area waters this weekend. Trades have already reached SCA
levels across the typically windier waters around Maui County and
south of Big Island. A SCA remains in effect for these windier
waters. There is a high likelihood of adding more coastal zones
to the advisory this evening or Saturday morning in response to
strong trades spreading westward over more nearshore waters.

The ongoing near three foot, medium period northwest (310 degree)
swell will flatten out today. A reinforcing small to moderate size,
long period northwest (310 degree) swell is forecast to arrive
through the day Saturday. Another slightly larger northwest swell
will be on this weekend swell`s heels and pass through Sunday
night through Monday. This early week swell will likely result in
High Surf Advisory surf heights along the better-exposed smaller
island north and west-facing shores. Short period easterly wind
wave swell will pick up going into the weekend as trade winds
pick back up. South-facing shore surf will remain at very low
background levels the next several days.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST this evening for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

&&

$$

DISCUSSION...Powell
AVIATION...Gibbs
MARINE...Blood


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