Area Forecast Discussion
Issued by NWS Honolulu, HI
FXHW60 PHFO 280637
Area Forecast Discussion
National Weather Service Honolulu HI
830 PM HST Thu Oct 27 2016
Breezy trade winds will continue through the weekend as high
pressure stays far north of the state. Passing low clouds and
showers will affect mainly windward and mountain areas, and may
reach leeward areas of the smaller islands at times. An upper level
trough will move over the state this weekend, resulting in wet trade
wind weather into early next week. Winds will also ease next week as
high pressure weakens.
Locally breezy trade wind weather continues across the state this
evening, as strong high pressure stays far north of the state.
Latest satellite imagery revealed areas of the low clouds in the
island vicinity as well as upstream east to northeast of the area.
These low clouds, riding on the winds will pass the area through
rest of the evening into early Friday morning. There are also high
clouds over the islands as well, adding to the cloudiness of the
skies over the state. Therefore, expect more passing showers to
affect the state at times, mainly over the windward and mountain
areas. Some showers will reach the lee areas of the smaller islands
The high far north will move southeast and weaken slightly in the
next couple of days. However, pressure gradient across the area
remains rather tight. Hence, expect the winds to firm up slightly
through the weekend. Airmass in the island vicinity will remain
somewhat stable for another day or so as a weak mid-level ridge
stays in the area. An upper trough will deepen and sag across the
state over the weekend, then linger nearby through early next week.
Falling mid-level temperatures will help to erode the inversion and
allow the airmass to become more unstable. Showers will become more
active this weekend, with heavier rainfall possible. On the other
hand, breezy trade winds will keep the showers moving, limiting the
amounts somewhat. Look for wet and breezy trade wind weather for the
islands over the weekend into early next week.
The overall synoptic weather pattern over the north Pacific is
rather progressive through next week, with fronts and high pressure
systems passing north of the state at times. Forecast solutions are
in fair agreement, with a ridge of high pressure eventually settling
just north of the islands later next week. This will lead to a
decrease of the winds over the state. A mid-level ridge is expected
to rebuild north of the area as well in the mean time, resulting in
a more stable airmass to return to the islands. Forecast is trending
toward a more typical trade wind weather for the state for next week.
High pressure north of the state will keep a breezy to locally
windy trade wind flow in place through Friday, with showers
focused primarily over windward and mauka areas. Some temporary
CIG/VSBY restrictions will be possible over windward locales,
mainly overnight through mid morning Friday. Elsewhere, VFR
conditions are expected to prevail.
AIRMET Sierra may be needed for mountain obscuration across
windward sections of some of the islands later tonight.
AIRMET Tango remains in effect for moderate low level turbulence
downwind of the mountains of all islands. These conditions are
expected to continue through Friday.
A Small Craft Advisory (SCA) remains in effect for all coastal
waters due to the breezy trades. Since the robust winds will prevail
through the weekend, so will the SCA. But then, forecast solutions
hint the winds may ease ever so slight just enough to be below SCA
level for a couple of windward coastal zones toward early next week.
Moreover, winds will trend downward next week as high pressure to
the north weakens, with improving conditions for much of the coastal
A series of small to moderate north and northwest swells will fill
in over the weekend and again toward the middle of next week, but
surf heights are expected to remain below advisory levels. A long
period east swell is possible this weekend from the distant
Hurricane Seymour in the Eastern Pacific. Furthermore, east facing
shores will see an increase in rough and choppy surf under the
breezy trades, possibly near advisory level in the next few days.
Small Craft Advisory until 6 PM HST Sunday for Oahu Windward
Waters-Oahu Leeward Waters-Kaiwi Channel-Maalaea Bay-Pailolo
Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island
Small Craft Advisory until 6 PM HST Sunday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Maui County Windward Waters-Maui County Leeward Waters-Big
Island Windward Waters.