941
FXHW60 PHFO 210121
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
321 PM HST Sat Dec 20 2025

.SYNOPSIS...
A few heavy showers and thunderstorms may linger through the
evening across Kauai and Oahu. Trade winds are expected to build
tonight becoming breezy Monday and Tuesday.

&&

.DISCUSSION...
A few heavy showers and thunderstorms may linger through the
evening across Kauai and Oahu as the system that brought heavy
rain across much of the state begins to fade. Light and variable
winds will shift easterly and strengthen tonight and Sunday,
eventually becoming breezy by Monday. Scattered to broken high
clouds will continue across the area through Sunday. Upper ridging
over the islands will keep an active system west of the area over
the next several days, but occasional high/layered clouds may come
in over the western half of the state at times.

A stationary front north of the islands will dissipate with trade
winds overrunning it, advancing the remnant moisture band over
the islands Monday and Tuesday. Otherwise, trades will focus
clouds and showers over the typical windward and mauka areas, with
breezier and wetter days (Monday and Tuesday) forcing more of the
showers leeward. Drier trades expected Wednesday and Thursday
before winds begin to veer east southeast on Friday through next
weekend ahead of a front.


&&

.AVIATION...
Lingering clouds and showers continue to move over the smaller
islands, bringing occasional MVFR conditions into tonight. The
Big Island continues to have primarily VFR conditions, but the
occasional shower moving overhead could bring brief MVFR
conditions.

Light winds will continue through tonight, but will gradually
strengthen tomorrow as the trade winds return. Showers embedded
within the trade winds will bring brief MVFR conditions to
windward and mauka areas.

AIRMET Sierra for mountain obscuration is in effect
for Kauai, Oahu, Molokai, and Lanai. Molokai and Lanai will likely
have conditions improve this evening, while Oahu and Kauai may
still have overnight mountain obscuration due to lingering clouds
and showers.

&&

.MARINE...
Slightly unstable southeasterly winds will gradually shift out of
the east and strengthen tonight as thunderstorm chances diminish.
Easterly trade winds will continue to increase Sunday as high
pressure builds far north of Hawaii and low pressure develops far
west of the islands. A Small Craft Advisory (SCA) will be needed
for the typically windy waters around Big Island and Maui Sunday
afternoon or evening and will likely expand to additional waters
as trade winds peak in strength Monday and Tuesday. Trades will
ease Wednesday and Thursday as the low to the west and high to the
north weaken, though SCA conditions may persist over the
typically windy waters.

Overlapping, moderate, medium period north (345-010 degrees)
swells will produce surf just below the High Surf Advisory level
during the peak this afternoon and evening. North swell will
gradually decline Sunday through Tuesday. A similarly sized north-
northeast swell is expected to arrive late Wednesday and persist
through Friday, with the largest swells favoring the eastern end
of the island chain.

For east facing shores, wrapping north swell will produce
moderate surf along exposed coastlines through Sunday, while
sheltered areas will experience small surf. Returning trade winds
will produce building surf on Monday, with rough conditions above
seasonal average possible Monday night into Wednesday. As trade
winds over and upwind of the islands ease during the second half
of the week, east shore surf will decline below average by
Christmas. Surf along south facing shores will remain very small
through the week.

&&

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

&&

$$


DISCUSSION...Foster
AVIATION...DT
MARINE...Wroe