Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 291407
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
400 AM HST Mon May 29 2017

.SYNOPSIS...
Light winds with land and sea breezes will continue one more day as
a weak pressure pattern lingers in the island vicinity. A few
windward showers will reach the area under the light easterly winds,
with clouds and showers shifting to leeward and interior areas in
the afternoon. Trade winds will return on Tuesday, becoming breezy
toward the weekend. Typical trade wind weather is expected for much
of the week, with passing showers affecting mainly windward and
mountain areas.

&&

.DISCUSSION...
Surface troughs lingering in the state vicinity continue to keep
synoptic winds light across the area early this morning. Nighttime
land breezes have brought some clearing to the islands, though
showers continue to affect the southeast Big Island at times. An
upper level trough is still present just east of the state at this
time. This feature should lift northeast slowly today, allowing the
airmass in the island vicinity to become more stable. Both early
morning Lihue and Hilo soundings reflected this trend. Lihue
sounding revealed a stable and rather dry airmass, while Hilo
sounding still showed an unstable airmass with near-normal moisture.

The aforementioned surface troughs are expected to persist in the
island vicinity for one more day. Thus, light winds will continue
across the islands, with land breezes early in the morning, becoming
seas breezes in the afternoon. Clouds will develop over the islands
in the afternoon and evening and may bring some showers late in the
day. As airmass is expected to become more stable, rainfall amounts
will be somewhat limited. Sensible weather will be hot and humid
during the day due to light winds.

High pressure will build north of the state tonight through Tuesday,
and will bring trade winds back to the islands. Low clouds and
showers carried by the winds will affect mainly windward and
mountain areas. Trades are expected to firm up a bit later this week
as high pressure lifts northeast and strengthens. Forecast solutions
indicated a somewhat stable airmass will prevail in the island
vicinity, with not much changes in the low level moisture.
Therefore, expect typical trade wind weather to return to state from
Tuesday through the weekend.

&&

.AVIATION...
A weak pressure pattern will remain in place through today, with
daytime sea breezes expected in most areas. Easterly trade winds
will begin to overspread the state from east to west tonight and
Tuesday. Showers will favor the coastal waters and windward areas
during the overnight and early morning hours, and the interior of
the islands during the afternoon and evening. Some brief MVFR
cigs/vsbys will be possible in SHRA over the island interiors
this afternoon/evening, but predominantly VFR conditions are
expected at the TAF sites through 12Z Tuesday.

No AIRMETs are currently in effect.

&&

.MARINE...
The higher than normal water levels experienced each day over the
weekend ended up breaking the April 29, 2017 record in Honolulu on
Friday and Saturday evenings due to a combination of sea level rise,
mesoscale features moving through the islands and King Tides. These
peak tides have begun to trend down and that trend is anticipated to
continue through the week. Coastal flooding impacts that have been
experienced around these late afternoon/early evening high tide
times over the weekend at the beaches, marinas and low-lying coastal
areas will likely occur once again around this evening`s high tide
before conditions trend back to normal. Peak daily high tides are
forecast to even dip below average (1.9 ft above MLLW) Thursday
through the weekend.

The large south swell that peaked Saturday and led to advisory-level
surf along south facing shores will continue to ease into Tuesday.
The offshore buoys south of the islands reflect this trend and show
the bulk of the energy focused within the 14-15 second bands. For
today, expect the largest surf through the morning hours with light
offshore winds. Onshore winds are expected to fill in by noon and
continue through the afternoon period as the surf fades. A series of
small background southerly pulses moving through will keep the surf
along south facing shores from becoming flat each day through the
upcoming weekend. For the long range, the latest models are not
supporting anything significant setting up within Hawaii`s swell
window near New Zealand through the first week of June.

An out of season small to moderate north-northwest (330 deg) swell
associated with a gale that developed near the Date Line over the
weekend and tracked east to around 1400 nm north of the state is
forecast to fill in Monday night across the local waters. This
source should peak through the day Tuesday well below advisory
levels, then trend down into the second half of the week.

Light winds with land-sea breeze conditions prevailing near the
coasts will continue into Tuesday morning due to a weak surface
trough located near the Big Island and northwest of Kauai. Trade
winds will gradually return Tuesday through midweek as high pressure
builds north of the area. Small craft advisory conditions will
likely result due to strong winds beginning Tuesday night and
persisting through the rest of the week. These stronger winds are
expected to setup over the channels, Maalaea Bay and south of the
Big Island. As a result, rough and choppy surf along east facing
shores is expected through the second half of the week and into the
upcoming weekend.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

Aviation...Jelsema
Marine...Gibbs
Rest...Hui


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