654
FXHW60 PHFO 200140
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
340 PM HST Fri Dec 19 2025

.SYNOPSIS...
Showers and thunderstorms will continue into tonight, mainly over
western islands. Light southeast surface winds will give way to
increasing trade winds late Saturday through into Monday. A new
area of increased moisture will move in Monday/Tuesday, with
mainly windward showers. Southeast winds are likely to return
late next week, but without as much moisture as our current
southeast flow situation.
&&

.DISCUSSION...
Showers with isolated thunderstorms have covered parts of the
state today, including a strongly rotating storm over Niihau early
this morning. This storm was strengthen in part by strong wind
shear and an interaction with an outflow boundary from previous
convection. The rotation was strong enough to have produced a
tornado, but due to the location of the event, we will likely
never know if one actually occurred. Heavy rain was reported in
several locations, including central Oahu, and flood advisories
were in effect for Kauai and Oahu earlier today. Showers have
moved mostly offshore as of 2 PM HST.

Additional showers and thunderstorms are in the forecast for
tonight into early Saturday, and short range ensembles showing
the main risk will remain over western islands. With light low-
level winds, the enhanced moisture that has impacted the state
this week will still be with us tonight and into Saturday. PW
values range from roughly 1.5 to 1.8 inches. Therefore, episodes
of brief moderate to heavy rainfall remain possible.

An important change in the weather is nearly here. After light
southeast winds tonight into early Saturday, trades will move back
late Saturday. They will become stronger out of the east Sunday,
and even stronger from just north of east Monday. A new area of
enhanced moisture will move in from the ENE around this time,
enhancing windward showers into early Tuesday.

Trades are forecast to last through Wednesday night, with
indications of a possible return to southeast flow late Thursday
into Friday.

&&

.AVIATION...
Widespread light to moderate showers with embedded heavier
convective elements are bringing MVFR to localized IFR conditions
to Oahu this afternoon. Ample moisture remains in place through
tonight as gentle offshore land breezes take hold over most areas.
Even with the land breezes, stout SW flow aloft will likely carry
pockets of moderate to locally heavy rain over leeward areas at
times.

Light winds then give way to afternoon sea breezes on Saturday
yielding the potential for convection over island interiors.
Trades return late saturday evening.

AIRMET Sierra for mountain obscuration remains in effect for Oahu.

&&

.MARINE...
Scattered to numerous showers and isolated thunderstorms will
continue over the western coastal waters tonight. While gusty
winds can be expected around any thunderstorms, generally gentle
to locally moderate southerly winds will continue, with light and
variable winds to the far northwest. By late this weekend,
easterly trade winds will gradually build from east to west with
the potential for SCA conditions over the windier waters and
channels around Maui County and the Big Island. Expect trades to
strengthen further early next week as surface high pressure builds
to the north.

The current moderate, medium period, north northwesterly swell
(340-350 deg) peaked yesterday evening and has been slowly fading
since. This north northwest swell will remain elevated through
this evening and keep surf just shy of advisory levels through
early Saturday along north facing shores. A small to moderate,
medium period, northerly swell is progged to fill in late
Saturday, along with a small, long to medium period west
northwesterly swell. This combination of swells may boost surf
heights back up Saturday night into Sunday, but should remain shy
of High Surf Advisory criteria. Sunday night into early next week,
the swell fades and should allow surf to drop to below seasonal
averages.

Surf along east facing shores will remain small given the lack of
trade winds upstream of the islands through Saturday, but areas
exposed to the north swell will see an uptick through the rest of
the weekend. As trade winds gradually strengthen later this
weekend, east facing shores could become rough and choppy Sunday
through early next week. Surf along south facing shores will
remain flat to tiny through the weekend into early next week.

&&

.FIRE WEATHER...
Showers, light southerly winds, and generally high relative
humidities will continue into Saturday. This will keep conditions
below critical fire thresholds through the next few days. The forecast
shows little chance for dangerous fire weather well into next
week.

&&

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

&&

$$


DISCUSSION...Parker
AVIATION...Farris
MARINE...JVC
FIRE WEATHER...Parker