393
FXHW60 PHFO 280642
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
842 PM HST Sat Apr 27 2024

.SYNOPSIS...
Moderate trades will prevail over the eastern islands through the
first half of next week, while light to moderate trades over the
western islands allow for some leeward land and sea breezes. A
plume of moisture will keep showery weather over windward areas
tonight and early Sunday. Drier conditions will then develop by
Sunday afternoon and persist through Tuesday, with a few showers
possible over interior and leeward areas each afternoon, while
showers will remain limited to mainly windward areas at night. The
trades will rebound Tuesday night and Wednesday, bringing a return
of more typical trade wind weather. The trades will become breezy
Thursday through next weekend, and the trade wind showers may
increase as well due to a disturbance aloft moving over the
islands.

&&

.DISCUSSION...
Currently at the surface, a front is located around 550 miles
west-northwest of Kauai, while a 1030 mb high is centered around
1300 miles northeast of Honolulu. Moderate to locally breezy trade
winds prevail over the eastern end of the state, while light to
moderate trades remain over the western islands. Infrared
satellite imagery shows mostly cloudy conditions in most areas,
with a bit less cloud cover over leeward sections of Maui County.
Radar imagery shows numerous showers moving into windward slopes
and coasts, with a few showers also in leeward areas of Kauai and
Oahu. Main short term focus revolves around trade wind trends and
rain chances during the next few days.

A front northwest of the state will gradually weaken into a trough
during the next few days as it edges slowly eastward. A slight
easing of the trades can be expected as we head into the first
couple days of the work week. Overall, moderate trades look to
hold on over the eastern islands, while lighter trades prevail
over the western islands, allowing some leeward sea and land
breezes to develop. We should see the trades start to rebound
beginning Tuesday night as the trough west of the state begins to
shift westward. Moderate to locally breezy trades should
overspread the state by late Wednesday, with the trades becoming
breezy across the entire island chain Thursday through next
weekend.

As for the remaining weather details, a band of moisture will move
through the islands overnight as a shortwave trough lifts
northeast across the state. This should keep windward slopes and
coasts showery, with a few showers affecting leeward areas as
well. A drier airmass is evident in satellite imagery east of the
Big Island, this in combination with mid-level ridging building
over the islands should bring a notable decrease in shower
coverage and intensity for most of the state by Sunday afternoon.
Shower activity should be rather limited in most windward areas
Sunday afternoon, although some leeward shower development will be
possible once again due to localized sea breezes. A more showery
Sunday afternoon can be expected on Kauai as the band of moisture
will be slower to exit here.

From Sunday night through Tuesday, relatively dry conditions
should prevail across the island chain. Brief passing showers
will be possible in windward areas each night, with a few showers
developing over interior and leeward areas each afternoon. We
should see a return to more typical trade wind weather Tuesday
night and Wednesday, with wetter trade wind weather potentially
developing Friday through next weekend as upper troughing sets up
over the state.

&&

.AVIATION...
A moist ESE flow will continue to provide a steady supply of
showers to windward and mauka areas of the Hawaiian Islands
overnight into Sunday morning, with tempo VFR conditions expected
within heavier showers. With a SE element to the winds, showers
will occasionally be steered across leeward areas.

Drier air will move in from the east on Sunday allowing conditions
to improve. With the lighter flow and less cloud cover, sea
breeze activity will be possible mainly during the afternoon
hours.

AIRMET Sierra for mountain obscuration is in effect for portions
of the Big Island and Molokai through Kauai. This AIRMET will
likely be needed through Sunday morning.

&&

.MARINE...
Surface high pressure, located roughly 1100 nm northeast of the
state, will drive breezy east southeast winds tonight, while an
approaching front lies far to the northwest. Through early next
week, this surface high will drift eastward and allow flow to
weaken. However, by mid-week, easterly flow will once again become
breezy.

A Small Craft Advisory for winds will remain in effect for most
waters and channels surrounding Big Island, Maui, and Molokai
through Sunday, but will likely be dropped by Monday as winds
weaken.

Surf heights will remain below advisory thresholds for all shores
through the forecast period. A small northwest, medium-period
swell will persist through mid- week with small surf expected.
Breezy east or east southeasterly flow will produce choppy surf
along east facing shores through Sunday, but will decrease as
winds taper off by early next week. Small, short- period
southeast, and small medium- period south swell will continue into
mid-next week. Surf heights along the south shore should remain
near or slightly below seasonal norms.

&&

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

&&

$$

DISCUSSION...Jelsema
AVIATION...Farris
MARINE...Thomas