Flash Flood Warning 11, NWS Honolulu, HI

830 
WGHW70 PHFO 100440
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
640 PM HST THU MAR 9 2017

HIC001-100445-
/O.CAN.PHFO.FF.W.0011.000000T0000Z-170310T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hawaii HI-
640 PM HST THU MAR 9 2017

...THE FLASH FLOOD WARNING FOR THE ISLAND OF HAWAII IN HAWAII COUNTY
IS CANCELLED...

Weather radar showed that heavy rain continues to ease.
A flood advisory...however...remains in effect.

LAT...LON 1950 15483 1948 15482 1939 15493 1943 15522
      1957 15524 1973 15500 1969 15498 1965 15499
      1956 15489 1952 15480

$$
Lau

Area Forecast Discussion
National Weather Service Honolulu HI
416 PM HST Thu Mar 9 2017

.SYNOPSIS...
Unsettled weather can be expected across portions of the state
through Friday as an upper level disturbance passes over the
island chain. Lingering moisture over the area will bring the
threat for locally heavy rain and a slight chance for
thunderstorms through tonight. A ridge of high pressure will build
in over the area this weekend with some showers still a
possibility especially over interior areas. Winds will remain
light over the weekend favoring a southerly direction. Trade winds
along with a drier weather pattern will gradually return next week
as a ridge of high pressure builds in just north of the state.

&&

.DISCUSSION...
An upper level trough can be seen on water vapor imagery near
Kauai. Instability associated with the trough along with abundant
moisture over the area will bring the risk for locally heavy
showers and a slight chance of thunderstorms tonight and possibly
on into Friday. At the surface, a weak trough lies in the island
vicinity resulting in rather light winds. The upper trough will
gradually move east tonight and Friday with the surface trough
gradually weakening in place. However the close proximity of the
upper trough along with lingering moisture will keep our weather a
bit unsettled through Friday.

Over the weekend, a front will be approaching the area from the
northwest. The western end of a surface ridge will lie across the
area. Low level wind flow will become southerly across the area.
Some volcanic emissions from Kilauea may spread up over the
smaller islands at that time. Moisture lingering over the area
will allow for some shower development to occur especially with
the help of daytime heating over interior areas. However confidence
on location and timing is rather low with no significant forcing
mechanism in place.

Into the long range, another front is forecast to stall and
weaken northwest of the area Tuesday and Wednesday with little in
the way of its associated rainfall expected across the area. In
the meantime, a surface ridge will begin to reestablish itself
just north of the area while a mid level ridge builds in over the
area as well. The expected result will be a gradual return of the
trades, though they may be light enough for local land and sea
breeze circulations as well. The mid level ridge will keep the
airmass rather stable so generally dry weather will be the likely
outcome.

&&

.AVIATION...
Thunderstorms have flared up around the state this afternoon, from
Oahu through Big Island. Max CB tops are between FL350-400.
Terminals have remained fairly quiet considering, with PHTO being
the most likely to see activity over the next few hours as the
storms slip down from upslope. Most thunderstorm activity over the
land should ease this evening. However, the chance for
thunderstorms will remain tonight as the upper level trough
fueling these storms continues to move east.

AIRMET TANGO for upper level turb is posted over the state for the
upper trough and jet stream. AIRMET SIERRA is posted over Oahu,
Maui, and the Big Island. This will be tailored as needed through
the night. Expect showers to bring MVFR to isol IFR conditions.

&&

.MARINE...
Observations at the nearshore buoys continue to run a few feet
higher than predicted this afternoon due to a large northwest
swell impacting the islands. Sea heights will likely remain high
through this evening, before slowly trending down below advisory
criteria (10 ft) late tonight through the weekend. As a result,
the small craft advisory has been extended through early Friday
morning. At the beaches, surf has lowered to advisory-levels, so
the High Surf Warning has been lowered to a High Surf Advisory in
effect through early Friday morning. Surf and swell will continue
their downward trend into the weekend.

Another gale-force low is forecast to develop several hundred miles
northwest of Midway near the Date Line Friday into the weekend. A
moderate west-northwest (310 deg) swell is expected from this source
Sunday night into the upcoming week. Models are in decent agreement
on this swell, but if it comes in slightly larger than predicted,
advisory-level surf will become a possibility late Sunday night
into Monday along exposed north and west facing shores of the
smaller islands.

Local winds will remain in the light to moderate category as a weak
front dissipates over the eastern waters today and a ridge builds
over the islands this weekend. Periods of heavy showers and
thunderstorms will remain in the forecast today due to a combination
of this weakening front and a disturbance aloft over the region.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through late tonight for all Hawaii islands.

High Surf Advisory until 6 AM HST Friday for Niihau-Kauai
Windward-Kauai Leeward-Waianae Coast-Oahu North Shore-Oahu
Koolau-Molokai-Maui Windward West-Maui Central Valley-Windward
Haleakala-Big Island North and East.

Wind Advisory until 6 AM HST Friday for Big Island Summits.

Small Craft Advisory until 6 AM HST Friday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters-Alenuihaha Channel-Big Island Windward
Waters.

&&

Synopsis/Discussion...Burke
Aviation...Eaton
Marine...TS

Special Weather Statement
National Weather Service Honolulu HI
253 PM HST THU MAR 9 2017

HIZ025-027-100115-
Big Island Interior-Big Island North and East-
253 PM HST THU MAR 9 2017

...A STRONG THUNDERSTORM WILL AFFECT WINDWARD SLOPES WELL ABOVE
HILO...

At 250 PM HST, a strong thunderstorm was located 13 miles southeast
of Pohakuloa Camp, or 20 miles west of Hilo, moving east at 5 mph.

Wind gusts up to 55 mph and nickel size hail are possible with this
storm as it approaches the eastern portions of Saddle Road.

LAT...LON 1952 15544 1970 15548 1978 15526 1952 15521
TIME...MOT...LOC 0050Z 259DEG 5KT 1963 15539

R BALLARD

Special Weather Statement
National Weather Service Honolulu HI
313 PM HST THU MAR 9 2017

HIZ008-010-100215-
Oahu Koolau-Central Oahu-
313 PM HST THU MAR 9 2017

...A STRONG THUNDERSTORM WILL AFFECT OAHU IN HONOLULU COUNTY...

At 312 PM HST, a strong thunderstorm was located upslope from
Mililani and Wahiawa, or 13 miles northwest of Honolulu. The storm
is nearly stationary. Wind gusts up to 50 mph and dime size hail are
possible with this storm.

Locations that could be impacted include...

Mililani, Wheeler Field, Pearl City, Wahiawa, Waikele, Ahuimanu,
Waiahole and Waikane.

LAT...LON 2156 15795 2141 15783 2141 15801 2147 15805
TIME...MOT...LOC 0112Z 276DEG 0KT 2148 15795

R BALLARD