922
FXHW60 PHFO 221331
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
331 AM HST Wed May 22 2024

.SYNOPSIS...
Moderate to locally breezy trade winds will continue over the
eastern islands. Lighter east-southeast winds will prevail over
the western end of the state which will allow for localized land
and sea breezes over mainly Oahu and Kauai. Clouds and showers
will generally favor windward and mauka areas, with a few showers
developing over interior and leeward sections of Oahu and Kauai
this afternoon and evening. Moderate to breezy easterly trade winds
will then spread over the state tonight into Thursday and linger
through the first half of next week, with showers favoring typical
windward and mauka areas.

&&

.DISCUSSION...
The latest surface analysis shows a trough of low pressure around
350 miles west-northwest of Kauai, with a 1036 mb high centered
around 1600 miles north-northeast of Honolulu. Satellite imagery
shows a mix of low and high clouds across the state early this
morning, with low clouds and a few showers favoring windward and
mauka areas. Moderate to locally breezy trade winds prevail over
the eastern islands, with light to moderate east-southeast winds
over Oahu and Kauai. Expect this pattern to continue through this
evening, with clouds and showers over typical windward and mauka
areas. Meanwhile, lighter winds over Oahu and Kauai will allow
for localized leeward sea breezes and isolated showers for most
sheltered areas this afternoon and evening.

Guidance continues to show the trough slowly shifting westward
today, but despite its proximity to the islands the heaviest
rainfall will remain west of Hawaii. Meanwhile, high pressure will
slowly shift north of the state later today, and a series of
reinforcing highs will build to our north through the first half
of next week. This will allow trade winds to strengthen across the
region, with moderate to breezy easterly trade winds expected
statewide by Thursday and continuing into much of next week.
Guidance also shows drier air filtering into the region over the
coming days. This will allow a more stable trade wind pattern to
develop. Expect windward and mauka showers to increase in
intensity and coverage during the overnight and early morning
hours, with a few of these showers briefly spilling over into
leeward areas. This pattern should hold through the first half of
next week.

&&

.AVIATION...
A moderate east to southeast flow will persist into Thursday with
a high pressure system to the northeast of the region. An area of
moisture remains over the eastern sides of the Big Island and Maui
overnight, bringing MVFR and pockets of IFR conditions to those
areas. Conditions have shown some improvements over the eastern
side of the Big Island in the last few hours, however satellite
shows additional clouds upstream that will be coming in a couple
of hours. AIRMET Sierra for mountain obscuration remains in effect
for these parts of Maui and the Big Island, and expecting that to
remain in place, possibly into tonight.

Windward clouds and showers have increased slightly, and may
increase some more over the next few hours. This will bring some
brief MVFR conditions to the remaining islands, but VFR are
expected to prevail.

&&

.MARINE...
Strong high pressure far northeast of the state is driving fresh
to strong easterly trade winds around the Big Island and Maui, and
a surface trough northwest of Kauai is causing winds to shift out
of the east-southeast over Oahu and Kauai. A Small Craft Advisory
(SCA) was extended through Thursday afternoon for all waters
around the Big Island, waters north of Maui, and the Pailolo
Channel. As the trough weakens and drifts westward, expect the
stronger easterly trades winds to spread to Oahu and Kauai, with
the SCA likely adjusted to cover the typically windy waters around
the Big Island and Maui County. Moderate to strong easterly trade
winds will persist into the weekend.

The south swell will continue to decline over south and exposed
west shores today. Only small long period background south swell
pulses are expected from Tasman Sea sources into the first half of
next week. The next long period south swell burst may reach island
shores by next week Friday May 31st.

Rough surf along east facing shores will slowly rise over the
next few days as the trades strengthen upstream of the state. Surf
heights along north and west facing shores will remain small with
a slight bump up from Sunday into Monday.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Thursday for Maui County
Windward Waters-Pailolo Channel-Alenuihaha Channel-Big Island
Windward Waters-Big Island Leeward Waters-Big Island Southeast
Waters.

&&

$$

DISCUSSION...Ahue
AVIATION...M Ballard
MARINE...Bohlin