Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 221931
AFDHFO

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

.SYNOPSIS...
Breezy northeast trade winds will continue through next week
focusing clouds and showers over windward and mauka areas,
periodically reaching leeward areas. An upper trough over the
state may enhance showers through tonight for Big Island but will
move southeast of the area by Saturday.

&&

.DISCUSSION...
Water vapor imagery shows an upper level trough directly over
Hawaii this morning. Meanwhile, a 1032 mb surface high is centered
around 950 miles to the northeast driving breezy trade winds
across the islands. Visible satellite shows scattered low clouds
and showers tracking southwestward and focusing over windward
slopes, particularly across the Big Island and Oahu. 12Z soundings
are fairly dry with precipitable water values of 0.95 at Lihue and
1.19 at Hilo. The trade wind inversion is present at Lihue, but
very weak at Hilo, and may result in some enhanced showers
through the day (in the afternoon for the leeward side of the Big
Island).

The upper trough will slide east of the state Saturday resulting
in increasing stability. Wind speeds are expected to gradually
increase through Saturday and maintain through the weekend as the
high to the northeast moves closer. Low clouds and showers will
continue track across the islands with the breezy winds, focusing
windward and mauka and occurring during the overnight and early
morning hours. Leeward sides of the smaller islands will also see
periodic showers as the winds carry them over the mountains.

Models show the upper trough closing to a low as it tracks south
of the islands and may bring some mid and high clouds over the
state early next week before crossing one last time as it fills in
and weakens. The high to the northeast will weaken Tuesday and
will quickly be replaced by another high by Wednesday, but bottom
line is the trade winds will stay breezy and continue to funnel in
windward clouds and showers through next week.

&&

.AVIATION...
Breezy NE trades will persist, with SHRA favoring
windward and mauka areas. The best windward SHRA 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
a slow upward trend in trade wind speeds over the next few days.
A Small Craft Advisory is currently in effect for the typically
windier waters around Maui County and the Big Island, but this
will likely be expanded in area later today or tonight as the
stronger trade winds become more widespread.

Surf along north and west facing shores will remain small today as
a small, medium period northwest swell fades. However, an
increasing trend will begin tonight as a reinforcing small to
moderate long period northwest swell arrives. This swell will
elevate north and west facing shore surf this weekend, though it
will likely remain below High Surf Advisory (HSA) levels. However,
a larger northwest swell will arrive Sunday, and will likely
result in HSA level surf for exposed shores Sunday night into
Monday.

Short period easterly wind wave swell will tren


&&

.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...Foster
AVIATION...Walsh
MARINE...Vaughan


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