Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 10/30/2026 04:45:00 PM UTC

                        
165
FXHW60 PHFO 300645
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
845 PM HST Thu Oct 29 2026

.SYNOPSIS...
The flooding threat over Big Island has diminished tonight with
improving conditions expected through early Friday. Lingering
light to occasionally moderate intensity showers will pass across
the state through Friday but the majority of this activity will be
too light to re-initiate flooding. Trade weather returns this
weekend with a frontal passage early next week significantly
limiting rain chances while producing a few days of very
comfortable, relatively cooler and drier conditions.

&&

.UPDATE...
Radar currently depicting the heaviest rain falling along Big
Island`s Hamakua Coast and Hilo regions, between Laupahoehoe and
Hilo, this evening. Since this afternoon, many gauges on or near
the Hamakua Coast have picked up 3 to near 8 inches of rain.
Overall, shower behavior is tapering off but there will still be
some cells over Maui County and Big Island that could easily put
down a quick half an inch to an inch of rain as they progressively
pass to the east. An afternoon ASCAT pass showed that trades are
in place across the windward near coastal waters. Weak lower to
mid level troughing still resides over the eastern half of the
state. A highly moist air mass of well above normal precipitable
waters (2.0 to 2.5 inches) within an unstable environment, as
evidenced by this afternoon`s Big Island thunderstorms, will
remain over the state through tomorrow. Thus, tonight and
tomorrow`s forecast calls for more of the same in terms of widely
scattered light to locally moderate intensity shower behavior.
Better organized rain clusters, especially interacting with
higher terrain, could again tip the bucket to having to issue a
Flood Advisory or two for nuisance-type flooding. Mid to upper
drier air will begin to work its way into the region this weekend
as a result of a passing North Central Pacific trough. So, after
another day of overcast and showery weather for many on Friday and
the first half of Saturday, the weather will begin to transition
to more drier with peeks of clear skies from as early as Saturday
evening onward into early Sunday.

&&

.PREV DISCUSSION...
Issued at 418 PM HST Thu Oct 29 2026

Latest satellite and radar imagery shows isolated thunderstorms
over windward Big Island this afternoon. While abundant low-level
moisture remains across the state with dewpoints in the 70s, drier
mid-level air has moved in over the western half of the state and
is shown on the 00Z sounding from Lihue. With the abundant low
level moisture still lingering over the western half of the state,
any passing showers will be capable of producing brief downpours
through Friday. Over the eastern half of the state, the drier
mid-level air should be moving in this evening into tonight.
Overall, with drier air moving in, and land breezes developing
over the Big Island, the current heavy showers and isolated
thunderstorms should taper off over the next few hours. So for
now, the plan is to keep the Flood Watch going through 6 PM today
with no extension anticipated as long as the current bands of
heavy rain begin to taper off over the next hour or so.

While the threat of flash flooding should be generally decreasing
overnight, some localized heavy rain is still expected over select
windward areas of East Maui and windward Big Island tonight
through Friday. Mid-level ridging building overhead should keep
the threat of any thunderstorms low and should bring stable
conditions by Friday afternoon.

For Halloween, weather conditions should generally be fair across
the state with gentle to moderate trade winds. Some low level
moisture may still linger over the eastern half of the state,
which will likely produce some scattered showers over windward and
mauka areas. Otherwise, fair weather should prevail for rest of
the state.

A strong high building behind a weak front passing near the state,
should produce strong northerly trade winds across the state by
Sunday evening. Dewpoints should get into the low 60s by Monday,
so relatively cool and breezy conditions should be expected on
Monday. A breezy to locally strong trade wind pattern is expected
early next week with scattered showers focused over windward and
mauka areas.

&&

.AVIATION...
Disorganized -SHRA/SHRA from Maui to the Big Island with trade
winds increasing for Kauai to Molokai. Embedded SHRA/+SHRA from
eastern Maui to the Big Island with VCTS/-TSRA for the windward
Big Island including PHTO. MVFR/VFR common this afternoon and will
persist into the evening with brief IFR CIGs/VIS under -TSRA/+SHRA.
Overall coverage of SHRA wanes a little overnight with increasing
trade winds for tomorrow.

Trade winds from Kauai to Molokai with more variable directions
from Maui to the Big Island. Gusty and erratic winds possible
around TS on the windward side of the Big Island.

AIRMET Sierra for mountain obscuration remains in effect abv 020
for Oahu, Molokai, Maui, Lanai, and the Big Island through North
to East areas. Conditions likely to persist into the evening.

AIRMET Tango for Turbulence remains in effect from Lanai to the
Big Island. Moderate turbulence between 100-FL200.

AIRMET Zulu is no longer in effect for light icing.


&&

.MARINE...
Issued at 418 PM HST Thu Oct 29 2026

Weak trough over the central waters will slowly move south and
dissipate Friday. This has continued to support showers and
isolated thunderstorms over the eastern waters and looks to
continue through this evening before conditions slowly improve.
Ridging to the north will gradually drive moderate to fresh
easterly winds over most waters Friday through the weekend. As
trade winds increase, a Small Craft Advisory for the windier
waters and channels around Maui County and the Big Island is
likely late this weekend into early next week.

The current northwest swell will gradually decline through the
evening before a small short period north-northeast swell will
fill in Friday and maintain small surf. A larger, long- period
northwest swell will arrive late Saturday and will likely push
surf above the High Surf Advisory threshold Sunday into Monday.
The swell will shift more northerly and may briefly build further
on Monday before dropping Tuesday. At the peak of the swell
coinciding with the 360 degree direction, a Marine Weather
Statement may need to be issued to due the potential for harbor
surges at Kahului and Hilo harbor.

Surf along south facing shores will slowly rise through this
evening, peak Friday just below High Surf Advisory levels, and
gradually decline through the weekend. By early next week, surf
looks to remain tiny to small through the forecast period.

Surf along most east-facing shores will remain small and choppy
through today but will rise Friday with the wrapping north to
north- northeast swell energy, producing periods of moderate surf.
Exposed shorelines to the north swell may be impacted along the
east side Sunday night into Monday with the potential for surf to
reach High Surf Advisory level surf possible.


&&

.FIRE WEATHER...
Issued at 418 PM HST Thu Oct 29 2026

Due to the recent rain and light wind, fire weather concerns will
remain low through Saturday. A front is expected to arrive early
next week. Breezy to locally strong north northeast winds and
drier conditions are expected in the wake of this boundary passage
late Sunday or early Monday. Thus, fire weather concerns will be
on the rise through next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Blood
DISCUSSION...Kino
AVIATION...Dye
MARINE...Shigesato