341
FXHW60 PHFO 270158
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
358 PM HST Fri Apr 26 2024

.SYNOPSIS...
Strong trade winds will gradually ease and veer toward the east-
southeast through early next week. Plumes of moisture will produce
passing showers across windward and mountain areas through
Saturday. A drier weather pattern is expected Sunday into early
next week with light to moderate east to east-southeast winds.
Winds should be light enough for sea breezes to develop during the
day and land breezes at night, especially early next week.

&&

.DISCUSSION...
A 1033 mb high far north-northeast of the state is currently
producing breezy easterly trades across the state this afternoon.
Latest satellite and radar imagery is showing scattered showers
mainly across windward and mountain areas this afternoon and the
Kona slopes of the Big Island. For tonight, shower activity will
generally increase, with showers focused over windward and
mountain areas and scattered showers over leeward areas. Latest
HREF model shows moderate showers over select windward areas
tonight, especially east Maui, which is a favorable area for rain
under the east-southeast flow.

Over the weekend, we should expect passing showers across the
state through Saturday morning. As the day goes on, we should see
showers generally decrease through the day Saturday with the
exception of leeward areas. With the trades veering toward the
east-southeast and weakening slightly on Saturday, this should
allow sea breezes to develop over leeward areas, which could lead
to afternoon clouds and some showers. A drier air mass should move
in by Sunday, so overall we should less showers on Sunday as well
as lighter winds with sea breezes developing over many leeward
areas Sunday afternoon.

For early next week, high pressure will be centered far northeast
of the state, while a low pressure system lingers north of the
state. We will be in a hybrid wind pattern early next week with
light to moderate east-southeast winds over windward areas and
generally light winds over leeward areas. Due to limited moisture,
we are not expecting much rainfall early next week, but some
light passing showers should be expected over windward areas, as
well as some light showers over leeward areas during the afternoon
with the sea breezes developing.

For the second half of next week, latest guidance is showing
quite a bit of uncertainty, but overall the GFS and ECMWF models
are showing some type of upper level trough over the area. The
ECMWF shows a much deeper upper level trough with a surface trough
developing near the state. Meanwhile, the GFS is showing a much
weaker upper level trough, with the surface high north of the
state maintaining trade winds during the second half of the week.
Stay tuned to the extended forecast, as the forecast will change
over the next several days. The current forecast aligns more with
the GFS due to it being closer to climatology for this time of
year.

&&

.AVIATION...
Locally strong ENE trade winds persist, but subtle veering and
weakening of the low-level flow is anticipated through tonight.
VFR is forecast to prevail, particularly leeward, aided by a
strong inversion anchored between 6-8kft. Isolated MVFR possible
within passing showers, mainly windward and mauka.

AIRMET Tango for lee turb remains in effect through today.

&&

.MARINE...
A 1033 mb surface high, centered around 1000 nm northeast of the
state, will remain nearly stationary through tonight and allow
moderate to locally breezy easterly trade winds to persist. From
this weekend through early next week, this feature is expected to
drift slowly eastward. Low pressure deepening well northwest of
Hawaii will help to gradually veer these winds east southeasterly
and weaken them.

A Small Craft Advisory (SCA) remains in effect for all waters
surrounding the Big Island and Maui county with the exception of
Maalaea Bay and the southeast Big Island waters. These areas are
typically less windy during easterly or east southeasterly flow.
As the flow weakens further tonight, most remaining zones will
likely be dropped from the advisory, leaving only the Alenuihaha
Channel by mid-Saturday morning.

Surf heights will remain below advisory thresholds for all shores
through the forecast period. A small northwest, medium period
swell will peak tonight, then slowly subside through the weekend.
Thus, expect small surf to continue along north and northwest
facing shores. Breezy trades will produce choppy, rough surf
along east facing shores through Saturday, which is expected to
lower later this weekend as easterly or east southeasterly flow
weakens. This afternoon, both Kaumalapau and Barbers Point buoys
showed energy from a 2 foot 10 to 12 second south southeasterly
swell, which matches guidance well. Expect small surf along south
facing shores through the forecast period with pulses of 1 to 2
foot medium to long period swell.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Saturday for Maui County
Windward Waters-Maui County Leeward Waters-Pailolo Channel-Big
Island Windward Waters-Big Island Leeward Waters.

Small Craft Advisory until 6 PM HST Saturday for Alenuihaha
Channel.


&&

$$


DISCUSSION...Kino
AVIATION...JVC
MARINE...JVC/Thomas