Wildfire in Hawaii, June 7 to 9, 2017

Area Forecast Discussion
National Weather Service Honolulu HI
1005 AM HST Wed Jun 7 2017

.SYNOPSIS...
Moderate trade winds are expected to prevail over the next week,
with a trend toward lighter trade winds possible over the weekend. A
relatively dry weather pattern will prevail over most areas the next
day or two, with just a few windward showers. An increase in
windward showers is expected from Friday into the weekend, as
moisture associated with a dissipated front moves over the area from
the north. Trade wind showers may stay active through early next
week, as a weak disturbance aloft will develop nearby.

&&

.DISCUSSION...
Seasonable trade winds will persist through the forecast period,
supported by persistent high pressure far north of the islands. The
high is currently centered about 1000 miles NNW of Oahu, and will
move toward the NE near 15 mph over the next couple of days. As the
high passes N and NNE of the islands Friday into the weekend,
moisture associated with a front that is now about 250 to 400 miles
N of Kauai will continue to sag slowly S toward the islands. Still
some subtle, but notable, differences between the ECMWF and GFS with
respect to how fast this band will move S. The ECMWF continues to be
faster in bringing the E-W oriented moisture band over the islands,
with windward showers increasing initially on Kauai Thursday and
Thursday night, spreading to Oahu and Maui county Friday into
Saturday. The GFS depicts a similar scenario unfolding a little more
slowly, with the official forecast depicting a general increase in
windward PoPs as early as Thursday, thus favoring the latest ECMWF
guidance. This boundary will be slow to clear the area due to its E-
W orientation, and the eastward motion of the high by that time.

So, it appears to be setting up to be a somewhat showery weekend, at
least over windward areas. This pattern continues through a good
portion of next week as models keep above normal moisture embedded
within the trade wind flow while a weak low aloft develops near or W
of the islands, acting to weaken the subsidence inversion.

&&

.AVIATION...
Early morning soundings from PHLI and PHTO show a strong low level
inversion between 4-5 kft. High pressure north of the state will
maintain moderate to locally breezy trade winds over the islands,
but are expected to remain below the threshold hold for widespread
low level turbulence.

Clouds and showers will focus along the windward and mountain areas.
Overall, showers should remain light with only brief MVFR CIGS/VIS
possible in select passing showers.

NO AIRMETS are expected today.

&&

.MARINE...
A Small Craft Advisory (SCA) has been issued for the typically windy
zones around the Big Island and Maui, and will extend through this
afternoon. Otherwise, no SCAs are expected over the next several
days as winds begin to ease and swells remain small.

Moderate trade winds will maintain relatively small, short-period
wind waves along most east facing shores through this weekend.
Small short-period swells from the northwest, north, and southeast
are possible through the rest of the week as well, but surf along
all shores will remain well below High Surf Advisory level. A small,
long-period south-southwest swell may arrive tomorrow and continue
through Saturday.

The coastal waters, especially north of the Big Island, will see
more showery conditions toward the end of the work week as a
dissipating, but moisture-laden, frontal boundary sweeps across the
area.

&&

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

&&

DISCUSSION...Birchard
AVIATION...Eaton
MARINE...Stall