Area Forecast Discussion
Issued by NWS Honolulu, HI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXHW60 PHFO 292127

Area Forecast Discussion
National Weather Service Honolulu HI
1127 AM HST MON AUG 29 2016

The Central Pacific Hurricane Center has issued a Hurricane Watch
for the Big Island and its surrounding waters. A Flash Flood
Watch has been issued for the Big Island starting Wednesday.


Moderate trade winds will continue for the next couple of days as
high pressure persists north of the state. A rather airmass is
expected over the islands through tonight, followed by an increase
in moisture on Tuesday. While considerable uncertainty remains
with the forecast track of Hurricane Madeline, direct impacts,
including damaging winds, flooding rain, and high surf, are likely
over portions of the state in the Wednesday and Thursday time
frame. Hurricane Lester may affect the islands over the upcoming
Labor Day weekend.



Stable trade wind weather will dominate through tonight, as
Hurricane Madeline, now roughly 650 miles to the east of Hilo,
advanced toward the state. A relatively strong 1028 mb surface
high will maintain moderate trade winds, while a mid level ridge
keeps the atmosphere rather stable. Moisture within the trade
wind flow will be below normal through tonight, keeping modest
rainfall focused along windward slopes.

Rainfall will increase on Tuesday as a large band of moisture on
the periphery of Hurricane Madeline moves over the islands. The
bulk of the shower activity will be focused along windward slopes,
though some showers will be carried across leeward areas at times.

Conditions on Wednesday and Thursday will be highly dependent on
the track and future intensity of Hurricane Madeline. The latest
track from the Central Pacific Hurricane Center (CPHC) shows
Madeline moving over or near the Big Island Wednesday night, and a
Hurricane Watch and Flash Flood Watch may be needed for some areas
today. Impacts from Madeline are becoming increasingly likely over
portions of the state, including the possibility of damaging winds
and flooding. There is higher confidence that the eastern end of
the state will experience surf above warning levels. It is
important for those in the State of Hawaii to not focus too
closely on the exact forecast track of Madeline. With an average
forecast track error of about 85 to 150 miles in the 48 to 72 hour
time range, it is still too soon to say with certainty which
islands could be directly impacted. It is also important to note
that significant impacts can extend well away from the center of a
tropical cyclone.

Distant Hurricane Lester may threaten the state during the
weekend. Residents and visitors are urged to closely monitor the
latest forecasts from the CPHC and NHC regarding these tropical


Moderate to locally breezy trade winds will continue today
allowing for clouds and showers to favor windward and mountain
areas. A slot of dry air will move over the islands today ahead of
an advancing Tropical Cyclone Madeline. This will help keep most
shower activity to a minimum today and prevailing VFR conditions
at all terminals. Deep tropical moisture surrounding Madeline
will start to reach the far eastern portion of the state Tuesday.

The 12z sounding from PHTO shows the inversion to be near 8 kft
and the sounding from PHLI shows a weak inversion near 4.5 kft and
another starting near 7.6 kft. Trade winds are expected to stay
just below the threshold for wide spread low level turbulence,
however periods of light turbulence may occur over and immediately
south through west of the mountains.


A Small Craft Advisory (SCA) remains in effect for Maalaea Bay
and the Alenuihaha and Pailolo channels through tonight. There
may be a slight downward trend in winds on Tuesday, but they
should pick up once again Wednesday and Thursday as Hurricane
Madeline approaches from the east. A Hurricane Watch has been
issued for all waters surrounding the Big Island.

No significant swells are expected through tonight. Winds and
seas, as well as surf along east facing shores, will increase from
east to west late Tuesday and Tuesday night with the approach of
Madeline. The east swell will likely peak at warning levels for
east facing shores of at least the Big Island and Maui on
Wednesday into Thursday. We will also start to see a long-period
swell from Hurricane Lester beginning Wednesday night or Thursday,
with surf building into the weekend, possibly to warning levels
along east facing shores once again. In addition, small surf from
distant Typhoon Lionrock will affect the state late Wednesday
through weekend.


Hurricane Watch for Big Island.

Flash Flood Watch from Wednesday morning through late Thursday
night for Big Island.

Hurricane Watch for Alenuihaha Channel-Big Island Windward
Waters-Big Island Leeward Waters-Big Island Southeast Waters.

Small Craft Advisory until 6 AM HST Friday for Maalaea Bay-
Pailolo Channel.



Update, Public, and Marine...Wroe
Aviation...Eaton is the U.S. government's official web portal to all federal, state and local government web resources and services.