Area Forecast Discussion
Issued by NWS Honolulu, HI
FXHW60 PHFO 040149
Area Forecast Discussion
National Weather Service Honolulu HI
349 PM HST Sat Dec 3 2016
An rather unsettled weather pattern can be expected through most
of next week as a trough of low pressure lingers near the area.
Locally heavy rainfall can be expected at times though not all
locations will experience these conditions. There will be breaks
in the weather at times with some sunshine possible as well. Winds
will be rather light for the most part favoring daytime sea
breezes and nighttime land breezes.
A weak low level trough is in place over the area. Thus winds are
light favoring daytime sea breezes and nighttime land breezes.
This low level trough is expected to linger over or just west of
the islands over the next several days.
Water vapor imagery shows two distinct upper troughs in our
vicinity. One trough is currently located just to the northeast
of The Big Island with a second trough seen digging down west of
Kauai. The trough northeast of The Big Island is moving toward
the north and will have less of an influence on our weather. The
trough digging down west of Kauai will be the main player for our
weather over the next few days.
With these features in place, a rather unsettled weather pattern
can be expected at times across the area. There is an abundant
amount of moisture in the island vicinity with the 00Z soundings
from both Lihue and Hilo indicating precipitable water values of
nearly 2 inches. Thus there is a chance for locally heavy
rainfall which is the reasoning for the Flash Flood Watch. There
is also a slight chance for thunderstorms with lightning currently
being detected over the waters west of Niihau.
A Winter Storm Warning has been issued for The Big Island summits.
Only light snow and freezing drizzle is expected overnight.
However another round of deep moisture is forecast to move over
the area Sunday and Sunday night with more significant snowfall
A brief break in the unsettled weather is expected later Monday
and on into Tuesday as the best upper dynamics pull away to the
north. However winds will remain light with some showers still a
By Wednesday, global models indicate a broad low level trough
will be located near or just west of the state. This will continue
to place the islands in moist southerly flow, though winds will
generally be light. A broad upper level trough will also be in
place in the island vicinity with its axis centered northwest of
the area. Thus periods of unsettled weather can be expected at
times during the Wednesday through Friday time period though
pinpointing the finer details such as timing and location is
problematic in the extended periods.
Afternoon clouds and showers developing over the smaller islands
this afternoon have brought additional areas of MVFR and
occasional IFR to those islands. As an upper level system moves in
from the west, expect more clouds and showers to impact the
AIRMET SIERRA was briefly dropped this afternoon, but has recently
been posted again for the smaller islands. The above mentioned
clouds and showers are bringing mountain obscuration to these
AIRMET TANGO remains in effect for moderate upper level
turbulence across the entire state between FL240 and FL400 due to
an upper level disturbance and upper trough in the vicinity of the
islands. These conditions are expected to remain in place through
AIRMET ZULU was canceled at noon, but may be needed again as the
new upper level system moves into the area.
East facing shores remain under a High Surf Advisory through
tonight due a moderate short-period east swell. Buoys exposed to
this swell continue to show seas near 7 to 8 feet, but this swell
will decrease tonight as the upstream fetch weakens.
A Small Craft Advisory (SCA) for most waters will remain through
tonight due to a combination of the east swell and a moderate
northwest swell. The SCA and High Surf Advisory are likely to be
dropped early Sunday morning. Winds will be light and variable
through much of the week. Surf is expected to remain below High
Surf Advisory levels through the forecast period.
Unsettled weather across the islands is expected through Sunday
night due to an upper level trough passing over the area. Heavy
rain and thunderstorms will be possible.
Flash Flood Watch through Sunday afternoon for all Hawaii
High Surf Advisory until 6 AM HST Sunday for Kauai Windward-Oahu
Koolau-Olomana-Molokai Windward-Maui Windward West-Windward
Haleakala-South Big Island-Big Island North and East.
Winter Storm Warning from 6 AM Sunday to 6 AM HST Monday for Big
Small Craft Advisory until 6 AM HST Sunday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Channel-Oahu Windward Waters-
Kaiwi Channel-Maui County Windward Waters-Alenuihaha Channel-Big
Island Windward Waters.