Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 240138
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
338 PM HST Wed Aug 23 2017

.SYNOPSIS...
A trade wind weather pattern can be expected over the next
several days, thanks to an area of high pressure far north of the
state. Passing light showers can be expected over windward and
mauka areas with most leeward locations remaining dry. Trade winds
will become lighter later this weekend and early next week as the
area of high pressure weakens. A wetter weather pattern is also a
possibility early next week as an area of tropical moisture moves
in from the southeast.

&&

.DISCUSSION...
A 1030 mb high is centered far north of the state. This places
the island in a moderate trade wind environment. Moisture embedded
in the trades is providing for a few passing light showers over
windward and mauka areas with most leeward locations remaining
dry. This weather pattern is expected to continue through
Saturday.

Later this weekend and on into early next week, the high is
forecast to weaken and move to a position far northeast of the
state. This will cause the trade winds to drop off to light to
locally moderate levels. More land and sea breeze circulations can
be expected under this lighter wind scenario. Also, models
indicate that an area of tropical moisture may move up over the
area from the southeast resulting in a more humid airmass in the
island vicinity. An uptick in shower activity is possible due to
increased moisture availability. Windward and mauka areas will
likely see an increase in showers while daytime heating will cause
for clouds and showers to form over interior areas during the
afternoon hours.

By Wednesday, high pressure will strengthen north of the area
with moderate trade winds returning. A drier airmass is also
expected to return with clouds and passing light showers once
again favoring windward and mauka areas.

&&

.AVIATION...
A breezy and relatively dry trade wind weather pattern is
expected through Thursday, with VFR conditions prevailing
statewide. Stable and showery low clouds moving in from the ENE
will provide brief periods of MVFR VIS/CIG in SHRA over windward
slopes and coasts, potentially affecting terminals in Lihue and
Hilo. AIRMET TANGO will remain posted for mechanical turbulence
near and downwind of the mountains.

&&

.MARINE...
High pressure passing north of the state has led to a
strengthening of the trade winds, with small craft advisory
conditions expanding beyond the typically windier areas near Maui
County and the Big Island to now include waters around Maui and
south of Oahu. Winds will start to decrease late in the work week,
with a greater decrease through early next week as the ridge
shifts southward toward the state.

The strengthening trade winds will also lead to choppy surf along
east facing shores. In addition, smaller, longer-period energy
from Kenneth well to the east may be around through Thursday.
South facing shores may see a bump this weekend as portions of a
Tasman swell reaches the islands.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Saturday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

Small Craft Advisory until 6 PM HST Thursday for Oahu Leeward
Waters-Kaiwi Channel-Maui County Windward Waters-Maui County
Leeward Waters.

&&

$$

Synopsis/Discussion...Burke
Aviation...Birchard
Marine...Bravender



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