Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 270634
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
834 PM HST Mon Jul 26 2021

.SYNOPSIS...
Moderate to breezy easterly trade winds will continue through
midweek, then strengthen Thursday through the weekend. Clouds and
showers will favor windward and mauka locations, especially
overnight through the morning periods. Areas of tropical moisture
moving through from east to west may enhance shower coverage and
intensity periodically. As the trades increase later in the week,
some of these showers may carry over into our dry leeward areas. A
return of drier trade wind conditions is anticipated this
weekend.

&&

.DISCUSSION...
Guidance remains persistent and continues to advertise plenty of
tropical moisture moving through the islands from east to west
through the second half of the week. This moisture combined with
an upper trough lurking nearby to the northwest will keep the
rainfall chances up, especially for the typical windward and mauka
locations each day. Some of the showers may become locally heavy
at times, and could spill over into our dry leeward areas later
in the week when the trades become locally windy.

For the upcoming weekend, rising upper heights and drier trade
wind conditions will limit rainfall chances, even for windward
areas.

&&

.AVIATION...
Moderate to occasionally breezy east northeasterly trades will
push showers across windward coasts and slopes through the
forecast period, especially along northeast portions of the Big
Island. Periods of MVFR ceilings and visibility will likely
accompany this activity. Isolated showers are expected elsewhere.
Expect VFR to dominate at most terminals.

AIRMET TANGO remains in effect for areas below 8000 feet over and
immediately south thru west of mountains for tempo moderate
turbulence.

AIRMET SIERRA remains in effect for north thru east sections of
the Big Island above 2000 feet for mountain obscuration from
clouds and showers and is likely to continue through tonight. This
AIRMET may have to be expanded to include windward portions of
Maui later tonight.

&&

.MARINE...
A high pressure system passing slowly north of the region will
keep fresh to locally strong trade winds in the forecast through
at least early Tuesday morning. A Small Craft Advisory (SCA) will
remain in effect for the typically windier waters and channels
near Maui County and the Big Island. This SCA may continue for the
same areas through Wednesday.

Moderate choppy surf along east facing shores will slowly trend a
bit lower tonight through Wednesday due to a slight weakening in
the trades near and upstream of the islands. A slight increase in
the trade wind swell and surf along east facing shores will develop
by Friday.

A mix of small south swells will keep surf small along exposed
south shores into the weekend.

A small west-northwest swell, from tropical cyclone activity in
the NW Pacific, may arrive along some exposed west and north
facing shores starting on Thursday or Friday. Confidence about
the timing and the size of these swells remains low at this time.

&&

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

&&

$$

DISCUSSION...Gibbs
AVIATION...Powell
MARINE...Bohlin


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