Current Conditions
Temp6.8 C
RH40 %
WindNNW 0 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

164
FXHW60 PHFO 270153
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
353 PM HST SUN JUN 26 2016

.SYNOPSIS...
High pressure centered far north of the state will maintain
moderate to breezy trades through the next few days. Clouds and
passing showers will favor windward and mauka areas of the smaller
islands, with mainly dry conditions leeward. The Kona slopes on
the Big Island will continue to see clouds and widely scattered
showers each afternoon and evening, followed by clearing skies
each night and morning. A wetter and more unstable trade wind
pattern is expected by midweek.

&&

.DISCUSSION...
Breezy trade winds remain this evening with only windward showers
expected. Trade winds will continue through the week with high
pressure firmly entrenched to our north. Limited moisture upstream
suggests a dry trade wind pattern will continue over the islands
for the next few days before giving way to wetter weather by
Wednesday.

Global models agree with a change in the upper level pattern this
week. Current conditions show the islands under an upper level
ridge with subsiding air creating a cloud capping temperature
inversion near 8 thousand feet. However, an upper trough rounding
the ridge from the north looks to bring cold air aloft over the
state late Tuesday, and remaining overhead into Friday. The cold
air aloft will remove the cloud capping inversion, allowing for
increased vertical cloud growth and the chance of heavier and more
plentiful showers. High pressure at the surface will remain
throughout, so trade winds will continue to push moisture into the
windward slopes where the majority of showers will fall. The
instability from the upper trough will allow for some of the
windward showers to reach leeward locations, with some downpours
possible.

If the forecast holds, there will be potential for enhanced
showers and even isolated thunderstorms from Wednesday into
Friday. The evolution of the upper trough will be monitored, and
modifications to the midweek forecast will continue as confidence
increases.

&&

.AVIATION...
High pressure north of the state will keep a moderate to locally
breezy trade wind flow in place through Monday. Clouds and
showers will focus primarily across windward and mauka areas, but
the trades will deliver occasional brief showers to leeward areas
as well. Brief MVFR cigs/vsbys will be possible in passing SHRA
in windward locales, with PHLI and PHTO the most likely TAF sites
to be impacted. Elsewhere, predominantly VFR conditions are
expected through the TAF forecast period.

No Airmets are currently in effect. Airmet Sierra may be needed
for mountain obscuration across portions of the island chain
Tonight.

&&

.MARINE...
A strong high far North Northwest of the area is producing locally
strong trade winds. The high will move South and weaken over the
next few days and the winds may drop below Small-Craft-Advisory
(SCA) strength by Tuesday. A strong new high will build Northeast of
the area through the second half of the week. The trade winds will
strengthen and could reach near-gale strength by next weekend.

A Southern Hemisphere swell will bring below advisory level surf
through Tuesday. As the trade winds strengthen later this week,
surf along east facing shores could reach advisory levels.

&&

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

&&

$$

Morrison...Public
Jelsema...Aviation
Donaldson...Marine

Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office