231
FXHW60 PHFO 211944
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
944 AM HST Fri Feb 21 2025

.SYNOPSIS...
Light winds and mostly dry conditions will prevail through early
next week, with a few showers possible along windward slopes and
coasts at night and over the island interiors each afternoon. A
series of cold fronts will approach from the northwest next week,
bringing an increase in showers, particularly over the western end
of the state around the middle of the week and again towards the
end of the work week.

&&

.DISCUSSION...
This morning`s radar and satellite imagery show a slight uptick
in clouds and showers across the eastern end of the state as a
plume of moisture moves in on the trades. Over the western half of
the state, clouds and isolated showers are favoring windward and
mauka areas as land breezes have helped to at least partially
clear leeward areas. A surface ridge centered well to the
northeast of the state will maintain light to locally moderate ESE
trades today that will allow for clouds and showers to generally
focus over windward and mauka areas, particularly this morning,
then transition to focus over leeward and interior areas with
afternoon sea breeze development. However, only light rainfall
amounts are expected with these brief passing showers due to
limited moisture and increasing stability as mid-level ridging
builds in from the west.

A progressive pattern to our north will bring a series of fronts
to our doorstep over the next several days, periodically
disrupting the trades and bringing an increase in showers to the
western end of the state. Between each front, the surface ridge
to the northeast of the state will try to reestablish itself, but
will have a hard time doing so as each front will be followed
closely by its successor. In this pattern, the main forecast
focus will continue to revolve around wind trends and rain
chances.

The first of these fronts will approach on Saturday into Sunday,
then dissipate northwest of the state. As this boundary
approaches, it will act to weaken the local pressure gradient and
maintain light winds across the region through early next week.
Since the moisture associated with this feature isn`t expected to
reach the state, rain chances will be driven by the light ESE
trades that will bring a few showers to windward areas overnight,
and land and sea breezes that will become more widespread allowing
for clouds and a few showers to build over leeward and interior
areas each afternoon and land breezes to bring partial clearing
overnight.

The second front will approach early next week and may increase
rain chances over the western end of the state Tuesday night into
Wednesday as the frontal boundary dissipates near Kauai. However,
model guidance shows both the boundary and its moisture field
mostly dissipating before reaching the state, so not expecting
much of an uptick in shower activity with this front either.

Then ahead of the third front, winds will turn southerly
Wednesday and Thursday, allowing the boundary layer to moisten up
and inversion heights to rise, bringing a slight increase in
shower activity, particularly over the western end of the state.
The third front looks to approach towards the end of the work
week, potentially bringing another, slightly more significant bump
in rain chances for the western end of the state Thursday night
into Friday.

&&

.AVIATION...
A surface ridge just north of the islands will support light to
moderate E to SE winds with localized sea breezes developing
during the day. Clouds will be on the increase in the afternoon
with a few light showers possible. Brief MVFR ceilings will be
possible with any shower development during the afternoon.

No AIRMETs are anticipated, but some brief MVFR ceilings will be
possible with the pocket of moisture moving into windward Big
Island and Maui this morning.

&&

.MARINE...
Strong high pressure over the northeastern Pacific, with a ridge
extending southwest to just north of Hawaii, will drive moderate
east-southeast winds through this morning. The ridge will shift
south today causing low-level winds to weaken and shift more
southeasterly by evening, becoming light and variable over the
western end of the island chain late tonight into Saturday. Light
to moderate easterly trade wind flow will return Sunday into next
week as high pressure rebuilds north of the state.

The current west-northwest swell will continue its gradual decline
through tonight. The next significant northwest swell is due late
Saturday into early next week with peak surf heights nearing and
potentially reaching warning levels along north and west facing
shores. Another similarly-sized northwest swell is expected to
build in Tuesday night and linger through Wednesday.

Small surf is expected along east facing shores over the next
week as trade winds remain light. Surf along south facing shores
should see a small boost through Saturday as a small south swell
fills in.

&&

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

&&

$$


DISCUSSION...Farris
AVIATION...Kino
MARINE...TS