059
FXHW60 PHFO 211355
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
355 AM HST Fri Aug 21 2026

.SYNOPSIS...
Weak trades today as a trough advances north of the islands.
Tropical Depression Two-C is still expected to track south of
Hawaii late Saturday into Monday. Even with the southward track
increased winds and rain are expected, with the highest rainfall
totals expected across windward and southeast Big Island.

&&

.DISCUSSION...

Surface troughing associated with tropical remnants positioned
immediately north of the Hawaiian islands will weaken the pressure
gradient today. As a result, light winds are expected with muggy
weather and dew points in the low 70s. A few afternoon showers over
leeward areas will be possible today.

The latest track from NHC continues to keep Tropical Depression Two-
C south of the islands. Confidence has increased further that the
main impacts from the system will be increased winds and heavy rain
potential over southeast and windward Big Island. Rain chances
will increase on the east side of the state late Saturday night
into Sunday, spreading west Sunday night into Monday. The current
rainfall forecast has 5 to 10 inches, locally higher, over the
Puna and Ka`u Districts and, to a lesser extent, the Hilo
Districts of the Big Island. Elsewhere, rainfall totals of 1 to 2
inches are expected, with isolated amounts up to 4 inches for
eastern Maui.

Breezy trades are expected to return Saturday into Sunday as
resident surface troughing lifts away from the area and Two-C lifts
out of the deep tropics. Trades then strengthen considerably as the
gradient responds to the close proximity of the tropical system and
1022mb high pressure anchored along 30N. Sunday may be quite windy
over the eastern end of the state with strong trades spreading
westward to the remainder of the state Sunday night through Monday.
There is still a chance that a portion of the area may be under
tropical watches/warnings during this time, but if the forecast
track continues to trend southerly chances of a tropical headline
will decrease.

Any shifts in the track will have impacts on both the rain and wind
forecast. A more southerly track may leave the smaller islands
relatively dry and in a more typical windy trade wind type of
pattern with more wind and heavier rain possible if the track shifts
north.

Stable, breezy trades establish for the remainder of next week as
the tropical system departs and governing high pressure centered
along 30N remains in place.

&&

.AVIATION...

A surface trough will continue to move west of Kauai this
morning, allowing for light flow to persist over the western half
of the state. In the wake of the trough, this afternoon, trades
will begin to fill back in and strengthen gradually across the
island chain from east to west. Trade winds will continue to
strengthen on Saturday and AIRMET TANGO will likely need to be
issued for low level turbulence.

Due to the lighter wind flow pattern, clouds and showers will
likely form over the interior regions and elevated terrain this
afternoon and then transition to mainly windward locations this evening
into tonight. VFR conditions are expected to prevail, except
for pockets of MVFR in clouds and showers.


&&

.MARINE...

A trough passing north of Kauai this morning will continue to
track northwestward and away from the state. As the trough moves
away, moderate to locally fresh trades will return later this
afternoon and could become locally strong tonight. A Small Craft
Advisory (SCA) will likely be needed for the windier waters
around Maui County and the Big Island by late tonight. Trade
winds will continue to strengthen over the weekend with gale force
winds possible across the windier waters around the Big Island as
Tropical Depression Two-C passes south of the state. A Gale Watch
will be possible for some of the windier waters around Maui County
and the Big Island late Saturday into Sunday. Across the offshore
waters, Tropical Storm conditions will be possible as early as
late Saturday. Tropical Storm conditions are expected Saturday
night into Sunday across the southern offshore waters.

Surf along south facing shores will see a modest increase today
from a new long-period south swell that began trickling in
yesterday. Another reinforcing swell is expected over the weekend,
which should boost surf heights near the summer average over the
weekend. A series of south swells are expected next week with
above average surf likely during the second half of next week.
Surf along east- facing shores remains below average with weak
trades, then is expected to build this weekend as the trades
restrengthen. Surf along east and south- facing shores will be
compounded by a southeast swell generated by Tropical Depression
Two-C that will build through Sunday and then become south, then
southwest through early next week. This short- period tropical
swell could cause surf to approach advisory levels along east
facing shores of the Big Island Saturday night into Sunday, though
forecast confidence is on the lower side as the wind field with
this tropical cyclone is expected to be relatively small and the
forecast track may shift slightly. North facing shores will remain
tiny through today, with a slight bump from Hurricane Lala
possible this weekend out of the west-northwest direction.


&&

.FIRE WEATHER...
Trades remain weak today then strengthen considerably over
the weekend as a tropical system passes south of the state. KDBI
values remain low in the wake of Hurricane Lala and relative
humidity is forecast to remain elevated during this period of strong
winds. The inversion remains in the 5-7kft range during this time.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Flood Watch from late Saturday night through Monday afternoon
for Big Island East-Big Island Interior-Big Island North-Big
Island South-Big Island Southeast-Big Island Summits-Kohala-Kona.


&&

$$

DISCUSSION/FIRE WEATHER...CO
AVIATION...Thomas
MARINE...Kino