Wildfire in Hawaii, November 17 to 21, 2016

Area Forecast Discussion
National Weather Service Honolulu HI
401 PM HST Thu Nov 17 2016

.SYNOPSIS...
High pressure systems passing to the north of the islands will
maintain breezy trade winds across the region into next week.
Clouds and showers being carried in on the trades will be focused
over windward and mauka areas. Some of the showers may reach
leeward areas of the smaller islands at times with the stronger
winds. Showers will increase over the weekend as an old frontal
boundary moves through.

&&

.DISCUSSION...
Moisture from a weakening frontal system north of the islands is
expected to sink southward over the next 48 hours or so, and will
bring an increase in low level moisture for this weekend. High
pressure north of region will maintain the breezy trades, so
expect the showers to remain focused over the windward portions of
the islands. That being said, the breezy trades will at times
carry the showers to leeward areas.

The high pressure system passing far north of the islands Saturday
will weaken some Sunday as it moves to the northeast of the
islands, however the resultant pressure gradient will have little
change, so not expecting much of a difference in the wind speeds.
A new, stronger high moves north of the islands by Monday night
which will keep the winds breezy. Sunday night will likely be the
point where winds may taper off a bit as we transition between the
two systems. This second high is forecast to sit to the north
northeast of the islands, and if anything strengthen as we head
into the middle of the new week. This will boost the trades
further on Wednesday and Thanksgiving.

The models continue to show an upper level trough digging in from
the northeast late in the forecast period. Earlier runs had the
ECMWF solution showing a stronger trough than the GFS, but the
most recent runs have the reverse. Its still in the long term
portion of the forecast so will continue to monitor future runs.
The trough will likely result in more shower activity across the
islands.

&&

.AVIATION...
Breezy trade winds will continue tonight with clouds and isolated
showers favoring windward and mountain areas. Conditions will
remain predominately VFR. Some passing showers may introduce
very brief periods of MVFR CIGS/VIS.

AIRMET TANGO for low level turb over and immediately south through
west of the mountains will remain posted. No other AIRMETs are
expected.

&&

.MARINE...
A north northwest swell is expected to arrive tonight, and will
bring advisory level surf to the north facing shores of Kauai and
Oahu around daybreak Friday, and shortly thereafter to the
remaining islands impacted. A high surf advisory has been posted
for the affected areas. The swell will also bring a rise in the
seas, so the Small Craft Advisory (SCA) that had been in effect
for the winds near the typical windier locations near Maui and the
Big Island this afternoon has been expanded to include all the
coastal waters areas. The combination of seas and/or winds will
maintain SCA criteria through Saturday. Beyond that, the winds are
expected to remain breezy enough for the SCA to remain posted
through the weekend for the typical windier locations. With
breezy winds expected through the forecast period, the SCA will
likely be extended.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory from 6 AM Friday to 6 AM HST Saturday for
Niihau-Kauai Windward-Kauai Leeward-Oahu North Shore-Oahu Koolau-
Olomana-Molokai-Maui Windward West-Maui Central Valley-Windward
Haleakala-Big Island North and East.

Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

Small Craft Advisory until 6 PM HST Saturday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters-Maui County Leeward Waters-Big Island
Windward Waters.

&&

DISCUSSION/MARINE...M Ballard
AVIATION...Eaton