Area Forecast Discussion
Issued by NWS Honolulu, HI

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438
FXHW60 PHFO 011335
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
335 AM HST Wed May 1 2024

.SYNOPSIS...
Moderate east to east-southeasterly winds will gradually build
today. Limited showers will remain focused over mainly windward
areas, with afternoon clouds and a few showers developing over
sheltered leeward terrain. Trade winds will strengthen on Thursday
and become breezy and gusty Friday through the weekend. Rainfall
will favor typical windward slopes, with an increase in showers
possible late this weekend through the first half of next week as
a disturbance aloft passes overhead.

&&

.DISCUSSION...
Stable east to east-southeasterly trade wind flow remains over the
islands early this morning as a weak trough northwest of the state
bisects a 1021 mb high to the far northwest and a 1030 mb high to
the distant northeast. Satellite imagery continues to show partly
to mostly cloudy skies across the region, with radar showing a mix
of isolated to scattered showers over mainly windward and mauka
areas. Expect trade winds to gradually strengthen today as the
trough to the northwest weakens further and high pressure starts
to consolidate to the north. However, wind should remain weak
enough this afternoon for local leeward sea breezes to develop
allowing for some afternoon clouds and isolated showers over
sheltered areas. However, with no organized areas of moisture
upstream of the islands and mid-level ridging maintaining stable
conditions expect rain totals to be limited today.

Guidance then shows the 1030 mb high settling to the northeast on
Thursday, with trade winds becoming more easterly and continuing
to strengthen. Breezy to locally windy trades are then expected
to develop by Friday and continue through the upcoming weekend.
This will drive a typical trade wind pattern with clouds and
showers favoring windward and mauka areas, especially during the
overnight and early morning hours.

The main wrinkle to the forecast remains the evolution of the
upper low currently to the distant northwest of the state.
Guidance shows this upper low slowly inching towards the state
over the next several days then stalling to the west of Kauai
over the weekend before moving over the state early next week.
This low should help to boost our trade wind showers late Sunday
into early next week. Guidance also shows an outside chance for
some isolated thunderstorms later this weekend into early next
week, but confidence is low.

&&

.AVIATION...
With a high to the northeast and a trough to the northwest winds
will remain light to moderate east to east-southeast flow through
Wednesday. Scattered SHRA with MVFR conditions expected windward
and mauka locations. Some isolated SHRA and MVFR conditions may
make it into leeward areas, but will be brief.

No AIRMETs are currently in effect.

&&

.MARINE...
High pressure far northeast of the state will shift south through
the rest of the week and dissipate as another high pressure
builds to the north. A weak trough to the northwest of the state
will shift far northwest of state. In response, moderate to
locally strong east-southeast winds will shift out of the more
typical easterly trades direction by Thursday, then strengthen to
fresh to locally strong Friday and holding into early next week. A
Small Craft Advisory (SCA) remains in effect for typical windy
waters around the Big Island and Maui through Thursday. This
advisory will likely be expanded to include additional waters
Thursday and Friday.

Tiny surf will persist along north and west facing shores through
Friday. A small, long period northwest swell is expected to fill
in Friday night, peak Saturday, bringing small surf along north
and west facing shores. A storm low currently near the Kuril
Islands will send another small, long period northwest swell late
Sunday that will maintain small surf along north and west facing
shores into early next week. Small background south swells will
continue through the week. A small, long period south swell may
fill in over the weekend providing a boost in surf along south
facing shores into early next week. Small, choppy surf along east
facing shores will gradually become rough and choppy Thursday
through the weekend as trades return.

&&

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

&&

$$

DISCUSSION...Ahue/Jelsema
AVIATION...Walsh
MARINE...Almanza