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RH6 %
WindENE 9 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

FXHW60 PHFO 270615

Area Forecast Discussion
National Weather Service Honolulu HI
830 PM HST Wed Oct 26 2016

Trade winds will persist across the main Hawaiian Islands through
early next week, becoming stronger in the next few days due to
a building high pressure to our north. A weak frontal cloud band
passing across the islands will keep skies cloudy with a few more
showers overnight into early Thursday. An upper level trough is
forecast to move near the state, and may result in wet trade wind
weather over the weekend into early next week.


A band of low clouds associated with a weak cold front is pretty
much over the islands this evening...bringing more showers to the
area. Much of the showers are affecting mainly windward and mountain
areas, though there are enough clouds to reach the lee areas of the
smaller islands at times as well. A ridge of high pressure far north
of the state continues to bring moderate to fresh trade winds across
the islands this evening. Airmass is still somewhat stable in the
island vicinity, and with moderate to fresh trades in the
background, these passing showers will be passing swiftly across the
area, limiting the accumulations. Expect the cloudy and showery
weather to prevail through rest of the evening into early Thursday

The weak front is still expected to continue its southward path and
will probably be clear of the island chain by early part of
Thursday. Therefore, weather conditions will be improving a bit
across the islands on Thursday. But then, forecast models indicated
there may still be some moisture behind the front lingering in the
island vicinity, providing some passing low cloud and showers at

The high pressure system far to the northwest will build east
southeastward over the next several days. Hence, expect stronger
trade winds to return to the state from Thursday night through early
next week. Upper level ridging will initially keep a cap on showers
Thursday night through Friday afternoon as the airmass in the
vicinity will remain stable. Rainfall amounts will therefore be
limited. An upper level trough is expected to move near the island
chain over the weekend into early next week. This will result in the
airmass becoming more unstable across the areas, allowing passing
showers to be enhanced. In the meantime, rather strong trade winds
are expected due to the strong high to the north. Thus, expect wet
and breezy trade wind weather for the areas by the weekend into
early next week, with passing showers reaching the lee areas of the
smaller islands at times.

A mid-level ridge may build back in island vicinity around Tuesday
of next week. Furthermore the strong high pressure to the north will
weaken at the same , which will lead to trade winds returning to
more moderate levels.


A band of enhanced moisture moving through the state will result
in widespread MVFR cigs/vsbys across windward locations this
evening, with improving conditions expected after midnight. Brief
MVFR cigs/vsbys may affect leeward areas this evening, but
predominantly VFR conditions are expected to prevail. AIRMET
Sierra remains in effect for mountain obscuration across windward
sections of all islands. Conditions should improve over the
smaller islands by midnight but may linger on the Big Island into
the early morning hours.

Strengthening trade winds are expected behind the enhanced band of
moisture, and AIRMET Tango will likely be needed for low level
turbulence downwind of the mountains of all islands later tonight.


Moderate trade winds with locally breezy conditions will remain
through tonight before the trade winds strengthen on Thursday. A
Small Craft Advisory (SCA) remains in effect for the typical windy
zones around Maui County and the Big Island through Thursday. The
SCA will likely be expanded to cover additional coastal waters as
the winds firm up.

A series of small to moderate north and northwest swells will fill
in this weekend and again towards the middle of next week, but surf
is expected to remain below advisory levels.

For the south facing shores, a small long period swell will bump
surf up slightly through Friday. A long period east swell is
possible this weekend from the distant Hurricane Seymour in the
Eastern Pacific. In fact, with the strengthening trade winds, east
facing shores will see an increase in surf heights.


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




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