High Surf and Heavy Rain in Hawaii, September 1 to 2, 2016

Area Forecast Discussion
National Weather Service Honolulu HI
907 PM HST WED AUG 31 2016

.SYNOPSIS...
Tropical Storm Madeline will track by just to the south of the
Big Island overnight with strong gusty winds and heavy rainfall
expected across the Big Island. Improving conditions are then
expected on Thursday across the Big Island as Madeline tracks
westward and well to the south of the smaller islands. Across the
rest of the state, a breezy to windy trade wind weather pattern
is expected through Friday. Moisture will begin to increase once
again Friday night in advance of Hurricane Lester, with the
potential for impacts to the entire state over the Holiday
weekend. A more typical trade wind pattern will resume by early
next week as Lester departs and high pressure builds well to the
north of the island chain.

&&

.DISCUSSION...
Currently at the surface, Tropical Storm Madeline is located
around 175 miles to south of Hilo, with Hurricane Lester around
575 miles to the east of Hilo. Meanwhile, a 1028 mb high is
centered around 1350 miles to the north-northeast of Honolulu.
Infrared satellite imagery shows overcast conditions over the Big
Island in association with Madeline, with partly to mostly cloudy
skies in place across the rest of the state. Radar imagery shows
widespread rain over windward sections of the Big Island with
isolated to scattered showers moving into windward sections of the
other islands. Main short term concern continues to revolve around
the impacts from Madeline.

Tonight and Thursday,
The latest track from the Central Pacific Hurricane Center (CPHC),
takes Madeline south of the Big Island overnight, then westward
and well to the south of the smaller islands during the day on
Thursday. Widespread rainfall and gusty winds will continue across
the Big Island tonight, with improving conditions expected on
Thursday as the deepest moisture associated with Madeline exits
to the west. Across the other islands, a breezy to windy trade
wind pattern will continue, with showers favoring windward and
mauka locales. Made some adjustments to POPs both tonight and
Thursday, primarily to lower rain chances over leeward sections
of the Big Island with Madeline to the south resulting in
downslope and drying conditions in this area.

Thursday night and Friday,
Based on the latest forecast tracks from CPHC, Madeline will
track westward and away from the area, while Lester tracks west
or west-northwestward toward the island chain. As a result, a
slightly drier airmass is expected across the state due to
subsidence on the periphery of the two tropical cyclones, with a
more typical, but breezy to windy trade wind pattern expected.

Friday night through Sunday night,
The latest track from CPHC continues to show Lester moving off to
the west-northwest over or just to the north of the islands
during the Holiday weekend. Deep moisture associated with Lester
will move into the eastern islands Friday night and will
overspread the remainder of the state on Saturday. Unsettled
conditions are then expected to continue through Sunday night in
association with Lester. Exact details will be highly dependent on
the eventual track of Lester.

Residents and visitors are urged to closely monitor the latest
forecasts in association with Lester from the CPHC, as impacts
are possible across all of the Hawaiian islands during the holiday
weekend.

Labor Day through next Wednesday,
Both the 00z GFS and 00z ECMWF show Lester moving northwest and
away from the state by early next week as deep layer ridging
builds to the north of the island chain. This should result in
improving conditions with a more typical trade wind pattern
becoming established across the Aloha state.

&&

.AVIATION...
As Tropical Storm Madeline weakens south of the Big Island, a few
lingering MVFR showers can be expected overnight at Hilo. After
18Z, the deeper moisture with Madeline will push southwest of the
Big Island and Hilo will return to more of a trade wind pattern
with some lingering MVFR ceilings possible. Aside from MVFR showers
in the vicinity and a few isolated showers, Kona will remain VFR
overnight. AIRMET SIERRA for tempo IFR conditions over windward
Big Island will remain into tonight.

For the remainder of the terminals, Madeline will serve to
tighten the pressure gradient with high pressure to the north.
This will allow for breezy northeasterly winds gusting to
20-30kts. MVFR showers can be expected at times for windward
locations, with mostly VFR conditions elsewhere.

AIRMET SIERRA highlights mountain obscuration along north and
east sections of the islands. AIRMET TANGO for tempo moderate
turbulence over and immediately south through west of the
mountains is posted for all of the smaller islands. See TC SIGMET
series ROMEO for area regarding turbulence and icing associated
with Madeline.

&&

.MARINE...
The combination of winds and seas resulting from Tropical Storm
Madeline and Hurricane Lester will result in hazardous boating
conditions in most marine zones through the weekend.

High surf can be expected along east facing shores in association
with Madeline. The largest waves will be along east facing shores
of The Big Island with heights becoming lower as you go up the
island chain. There will also be a bit of an increase along some
south and west facing shores once the system moves west of The Big
Island.

Surf along east facing shores associated with Madeline will ease or
lower on Thursday for a brief period before rising once again in
response to Hurricane Lester approaching the region from the east.
Surf will likely reach warning levels along the exposed east facing
shores of all islands over the weekend.

Winds, seas and surf will diminish after the passage of Lester
with a typical trade wind pattern setting up.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 PM HST Thursday for Kauai Windward-
Oahu Koolau-Olomana-Molokai Windward-Maui Windward West.

Flash Flood Watch through Thursday afternoon for Big Island.

Tropical Storm Warning for Molokai-Lanai-Kahoolawe-Maui-Big
Island.

High Surf Warning until 6 PM HST Thursday for Windward Haleakala.

Tropical Storm Warning for Maui County Windward Waters-Maui
County Leeward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha
Channel-Big Island Windward Waters-Big Island Leeward Waters-Big
Island Southeast Waters.

Small Craft Advisory until 6 PM HST Thursday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel.

&&

DISCUSSION/MARINE...Jelsema
AVIATION...Woodrum

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
641 PM HST WED AUG 31 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1103 AM     NON-TSTM WND GST 5 NNE KAWAIHAE          20.11N 155.80W
08/31/2016  M60.00 MPH       HAWAII             HI   MESONET

            KOHALA RANCH REPORT. SUSTAINED WINDS REACHED 44 MPH AT
            238 PM HST.

&&

CB