Waimalu, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

673
FXHW60 PHFO 220146
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
346 PM HST Sun Dec 21 2025

.SYNOPSIS...
High pressure will strengthen trade wind speeds Monday into
Tuesday, then taper off Wednesday through the end of the week. A
remnant front will increase showers Monday into Tuesday focusing
windward and occasionally reaching leeward sides. Drier and more
stable trade winds expected from Wednesday to Friday.

&&

.DISCUSSION...
A strong high far north northwest of the area will slowly dig
southeastward and tightening the gradient between a stationary and
persistent low pressure system west of the main Hawaiian Islands.
As a result, trade winds will be increasing through Monday and
maintaining Tuesday before weakening as the high is squeezed
between two lows.

Moisture from a remnant front will make its way southward as the
ridge builds, bringing clouds and showers to the area Monday and
Tuesday. The band will track north to south, but easterly trades
will focus showers windward, but occasionally reaching leeward
sides as well.

Lighter and drier trades are expected Wednesday as a more stable
airmass propagates across the islands, persisting through the
reminder of the week. Model guidance remains in reasonable
agreement, proposing another frontal boundary just west of the
islands toward the end of the outlook period. Further analysis
will be necessary to determine the timing and impacts of this
front, as confidence remains too low for now.

&&

.AVIATION...
The trade winds have gradually returned today across the state,
with some locations in Maui County experiencing gusty winds.
Expect the winds to continue strengthening tomorrow, which may
warrant AIRMET Tango to be issued for low level turbulence
downwind of terrain. Showers embedded within the trade winds may
bring brief MVFR conditions to windward and mauka areas.
Otherwise, VFR will prevail.

There are no AIRMETs currently in effect.

&&

.MARINE...
Building high pressure will favor fresh to locally strong trades
through the week, peaking at near-gales on a localized basis
during Tuesday. Winds veer to SE this weekend in advance of low
pressure. The Small Craft Advisory for winds remains in effect.

Modeling indicates remnants of the existing NNW is on its way out,
confirmed by nearshore PacIOOS Buoys for Waimea Bay, Mokapu Point,
and Pauwela which are dominated entirely by N (350-010) swell through
the medium and long period bands today. The nearshore observations
indicate this swell has held steady for the balance of today,
though indications from offshore NDBC 51000 are that it will
resume trending downward tonight into tomorrow. Forerunners
associated with a building moderate N to NNE (010-020) swell are
forecast to arrive by late Wednesday bringing moderate surf to
favored exposures Thursday into Friday night. A Marine Weather
Statement (MWS) is in effect for moderate harbor surges associated
with the current N swell, and another MWS may be needed for the
next swell in the sequence Wednesday night through Friday.

Returning trades produce building surf along E facing shores
beginning today and peaking with building trades on Tuesday. Surf
then diminishes during the second half of the week as trades
weaken and veer to SE. Surf along S shores remains tiny with
fleeting background S to SSW energy through the week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Tuesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...Foster
AVIATION...DT
MARINE...JVC