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679
FXHW60 PHFO 010701
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
901 PM HST Tue Apr 30 2024

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

.DISCUSSION...
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Hawaii remains under a stable east to east-southeasterly trade
wind flow as a weak trough far northwest of the state bisects a
pair of high pressure systems to the distant northeast and
northwest. There remains no organized areas of moisture upstream
of the islands, with mid-level ridging maintaining stable
conditions across the area. Local sea breeze clouds and showers
that developed over sheltered leeward areas this afternoon
continue to dissipate this evening, with a few showers across
windward slopes.

Trade winds will gradually strengthen and become more easterly
Wednesday and Thursday, as the trough to the northwest fills and
surface high pressure consolidates to the north. Winds will likely
be weak enough for some leeward sea breezes Wednesday afternoon,
but aside from typical showers on the South Kona slopes of the Big
Island, chances for leeward rainfall will be minimal. Continued
westerly flow aloft may bring some patches of thin high clouds.

A 1030 mb surface high will settle far north of the state late
Thursday and Friday, driving breezy and gusty trade winds and
mainly windward rainfall into early next week. A compact upper-
level low lingering west of the state Thursday and Friday will
eventually move overhead during the weekend. Confidence in a
significant boost in shower activity is not high at this time,
though the highest chances for enhanced shower activity looks to
be on Sunday and Monday.
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&&

.AVIATION...
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Hawaii remains wedged between a pair of surface high pressure to
the distant NE and NW and a trough to the far NW. This will
maintain light to moderate E to ESE flow into Wednesday. Expect
scattered SHRA along the windward and mauka portions of the
islands, most active at night and early morning, and isol SHRA
possible leeward. Brief periods of MVFR cigs/vsbys are possible.

No AIRMETs are currently in effect.
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&&

.MARINE...
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High pressure far northeast of the state will shift south through
the rest of the week and dissipate as a new 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. A Small Craft Advisory (SCA) is now in
effect for typical windy waters around the Big Island and Maui.
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 will is expected to
fill in Friday night and peak Saturday brining small surf along
north and west facing shores. Another developing storm near the
Kuril Islands will send another small, long period northwest swell
late Sunday, peaking early next week, maintaining small surf
along north and west facing shores. Small, long period background
south swells will continue through the forecast period keeping
small surf along south facing shores. Small, choppy surf along
east facing shores will gradually become rough and choppy Thursday
through the weekend as trades return.
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&&

.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/Wroe
AVIATION...Walsh
MARINE...Almanza