Waimea, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

385
FXHW60 PHFO 240247 AAA
AFDHFO

Area Forecast Discussion...UPDATED
National Weather Service Honolulu HI
447 PM HST Fri Jan 23 2026

.UPDATE...
As an upper level trough passes over the state, temperatures at
the Big Island summits have dropped below freezing. With these
cold temperatures and deep moisture over the summits, snow
showers and freezing fog are expected to continue to impact the
Big Island summits this afternoon into the evening hours. Blowing
snow and freezing fog will reduce visibilities and snow and ice
accumulations will make road conditions hazardous. A Winter
Weather Advisory has been issued for the Big Island summits due to
these hazardous conditions.

This pattern may emerge again tomorrow afternoon as daytime
heating sparks convection over the Big Island, moisture lingers,
and the upper level trough remains in the vicinity before moving
off to the east.

&&

.SYNOPSIS...
A moist air mass will linger over the islands through the
weekend, with showers favoring windward and mauka areas tonight as
moderate easterly trades redevelop. Winds will weaken and veer
east-southeasterly Saturday, then become light and southerly on
Sunday, allowing land and sea breezes to dominate and drive
afternoon showers over interior and leeward areas. Forecast
confidence decreases early next week as one or more weak fronts
approach the state, though limited upper-level support should keep
rainfall impacts modest.

&&

.PREV DISCUSSION.../ISSUED 324 PM HST Fri Jan 23 2026/

A moist and somewhat unstable air mass remains in place across
the state this afternoon. Light to moderate east-northeasterly
winds are present over the western islands, while light east-
southeasterly winds continue over the eastern end of the island
chain. Earlier today, weak low-level convergence along a fading
surface boundary over the central islands provided the focus for
locally heavy rainfall and isolated thunderstorms. That boundary
will continue to weaken tonight, allowing moderate easterly trade
winds to become more uniform across the area as high pressure
slides eastward north of the state. As a result, clouds and
showers will focus over windward and mauka areas overnight.

Looking ahead to the weekend, that same high pressure system will
continue shifting eastward in advance of the next front
approaching from the northwest. This will cause winds to gradually
veer east-southeasterly on Saturday, then weaken further and turn
southwesterly across the western half of the state by Sunday.
With this lighter background flow, land and sea breezes will
become more dominant each day. Meanwhile, the upper-level trough
that has been supplying instability will slowly pull away to the
east, allowing atmospheric stability to increase from west to east
as mid-level ridging builds in. That said, the air mass will
remain quite moist and some instability will linger, especially on
Saturday. Model guidance keeps precipitable water values well
above seasonal averages through the weekend, so even with
improving stability, isolated to scattered showers are still
expected, especially across interior and leeward areas each
afternoon where sea breeze convergence sets up. While an isolated
thunderstorm cannot be ruled out, the probability remains too low
to include in the forecast at this time.

Forecast confidence decreases heading into next week as models
continue to struggle with the timing of an early-week front, and
even more so with a possible follow-up front later in the week.
With mid-level ridging forecast to persist over the state, these
fronts are expected to arrive with limited upper-level support.
That should keep shower activity fairly modest and allow the
cooler air masses behind them to only briefly influence the
islands before sliding east. For the first front early next week,
the 12Z ECMWF is faster than the latest GFS, bringing the boundary
through early Monday, while the GFS delays passage until later
Monday into Tuesday. Behind the front, winds are expected to
quickly veer easterly, then southeast on Tuesday, before weakening
and turning southerly by Wednesday. This would once again favor a
land and sea breeze regime midweek, ahead of another potential
front toward Thursday or Friday.

AVIATION...
Scattered showers, some with heavy rain, have mostly ended.
Isolated showers continue over portions of Maui County as of mid-
afternoon, with most other locations remaining dry. Winds will
remain light (5-15 mph) and mostly out of the northeast, but will
begin to veer easterly tonight, and southeasterly Saturday.
VFR conditions are expected in most areas, but showers with
isolated MVFR are forecast for Saturday.

No AIRMETs in effect.

MARINE...
High pressure currently north of the state will drift eastward
over the weekend as another front approaches the state from the
northwest. Moderate trades will veer to a more southeasterly
direction on Saturday then become light southerlies Saturday night
into Sunday. Winds should become light enough for land and sea
breezes to develop during this time. The tail end of the cold
front will likely move through the state late Sunday into Monday
with strong north to northeast winds following behind the front.
There is still some uncertainty regarding the timing and the
strength of the winds behind the front and the forecast should be
fine tuned in the coming days.

The current medium period north-northwest (330-340 degree) swell
will continue to decline tonight into Saturday. Surf heights have
fallen below advisory thresholds and the High Surf Advisory has
been cancelled. A series of small overlapping northwest swells
will maintain below average surf over the weekend through early
next week. The first pulse should arrive late Saturday and peak on
Sunday, followed by another pulse late Monday. A slightly larger
north-northwest (330 degree) swell is expected Tuesday into
Wednesday. In the long range, there is potential for a large
long-period northwest towards the end of next week, but the
latest ECWAVE guidance seems to be trending lower, while the WW3
guidance continues to stay persistent with a warning level swell
by the end of next week. Current forecast continues to reflect the
WW3 solution, but stay tuned for updates over the next few days.

Surf along east-facing shores will remain small into next week
due to the lack of persistent trade winds locally and upstream.
South-facing shores will remain nearly flat through the weekend.
A tiny long-period south-southwest swell is possible Monday into
Tuesday.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM HST Saturday for Big Island
Summits.


&&

$$


UPDATE...Farris
DISCUSSION...Farris
AVIATION...Parker/Kino
MARINE...Kino