047
FXHW60 PHFO 290150
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
350 PM HST Wed Oct 28 2026

.SYNOPSIS...
The flood threat will continue through tonight for Oahu through
the Big Island as a surface trough shifts over the eastern half of
the state in the midst of deep tropical moisture and modest
instability. Conditions are expected to improve heading into
Thursday, with moderate trade winds returning this weekend. A
front is expected to sweep down the island chain Sunday and Sunday
night, bringing breezy northeast winds and drier conditions
through midweek.

&&

.DISCUSSION...
This afternoon`s radar and satellite imagery show a messy weather
pattern across the state. There are currently three main focus
areas for deep convection and heavier showers: the first is along
a nearly stationary convergent boundary in the Kaiwi Channel,
another is along a diffuse surface trough extending over the Maui
County coastal waters from the southwest and bringing showers to
the Kona and Kohala Districts of the Big Island, and the third is
over the east and southeast facing slopes of the Big Island in the
southeast flow. Otherwise, light to moderate showers are setting
up over the Ko`olaus, which may become another focus this evening.

Overnight, the focus will remain on these convergent boundaries
and along any areas where showers manage to anchor on the terrain.
An upper level shortwave trough will pass eastward over the state,
likely helping to enhance these areas of heavier showers and then
shifting them east of the island chain by Thursday. Even while
scattered to numerous showers are expected to continue across Oahu
through the Big Island where the deep tropical moisture remains
concentrated along with weak surface convergence, rain rates
should be manageable on Thursday. As such, the Flood Watch that
goes through tonight will likely not be extended and has been
trimmed back to remove Kauai and Niihau where drier air is
filtering in.

Moderate east-northeast trades will gradually fill in from west
to east across the island chain Thursday through Friday, shifting
the focus for showers over windward and mauka areas.

The next pattern shift is on track for Sunday into Sunday night,
when the global models show a front barreling down the island
chain from the north, with breezy northeast winds and noticeably
drier air filtering in behind it. These breezy trades and drier
conditions are expected to last through midweek next week.

&&

.AVIATION...
Two areas of disorganized -SHRA with embedded +SHRA between Oahu
and Molokai with the second area between Maui and the Big Island.
Both areas have remained fairly stationary this afternoon, but
could drift north or south with time, which could impact PHNL/PHJR
and PHMK. In addition, PHTO/PHKO could also see instances of
+SHRA/RA. All of these locations could see periods of IFR under
+SHRA/RA due to low VIS/CIGs. Low confidence of VCTS/TS and it is
not included in TAFs. Improving VIS/CIGS from NW to SE generally
after 29/08Z to more of a VCSH/-SHRA pattern. Kauai will remain NW
of the activity with VCSH and usual trade wind flow. By tomorrow,
the islands will gradually transition back to easterly trade
winds with VCSH/-SHRA.

Surface winds remain generally weak. However, thunderstorms could
bring brief gusty and erratic winds.

AIRMET Sierra for mountain obscuration remains in effect abv 020
for Oahu through the big Island due to the the widespread low
clouds and pockets of moderate to heavy rain showers.

AIRMET Tango for Turbulence for Oahu to the Big Island. Moderate
turbulence between 100-FL200.

AIRMET Zulu is in effect for light ice from Oahu to the Big
Island in layer 140-FL200 with conditions expected beyond 29/04Z.

&&

.MARINE...
The end of a surface trough southwest of the islands extends into
Maui County waters this afternoon, and a broad weakening surface
low centered roughly 900 nm northeast of the state is keeping the
local pressure gradient somewhat weak. As a result, moderate
easterly prevail north of the trough with lighter southeasterly
winds to the south and east of the trough. The trough will
continue to build eastward over Maui County waters tonight and
will provide a focus for scattered heavy showers and isolated
thunderstorms, some of which could produce erratic localized wind
gusts over gale force. The trough will weaken near the Big Island
Thursday, allowing building ridging to the north to drive
moderate to fresh easterly winds over most waters and southerly
winds near Big Island. The trough will move south of Big Island
Friday, and moderate to locally fresh trades will prevail Friday
night into the weekend. Stronger northeast winds will likely
require a Small Craft Advisory late Sunday and Monday.

A small northwest swell will continue a slow decline through
Thursday then fade on Friday, but a small, short-period north-
northeast swell will maintain small surf along northern shores
during the next few days. A larger, long-period northwest swell
will arrive late Saturday and may push surf above the high surf
advisory threshold Sunday. The swell will shift more northerly and
may briefly build further on Monday before dropping Tuesday.

A series of overlapping south-southwest swells will maintain south
shore surf above seasonal average through the weekend. Surf along
south-facing shores will decline to around seasonal average early
next week.

Surf along most east-facing shores will be dominated by wrapping
north to north-northeast swell energy, producing periods of
moderate surf. Strong northeast winds and a large, rough north-
northeast swell are possible Sunday night and Monday.

&&

.FIRE WEATHER...
Fire weather concerns will be low through Saturday due to a
combination of deep tropical moisture helping to supply showers
across the state and light to moderate winds. A front is expected
to barrel down the island chain Sunday through Sunday night,
bringing breezy northeast winds and drier conditions in its wake.
As such, fire weather concerns will become moderate Sunday or
Monday through midweek next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for Oahu, Molokai, Lanai,
Kahoolawe, Maui and the Big Island.

&&

$$

DISCUSSION...Farris
AVIATION...Michael
MARINE...Wroe
FIRE WEATHER...Farris