749
FXHW60 PHFO 181318
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
318 AM HST Wed Sep 18 2024

.SYNOPSIS...

Moderate to locally breezy trade winds will hold through the
weekend. A more typical dry season trade wind pattern is expected
to return today and hold through Saturday with passing showers
focused over windward slopes.

&&

.DISCUSSION...
Satellite and radar imagery early this morning shows an area of
numerous clouds and showers moving mainly Oahu and Kauai. This
enhanced area of showers will continue to provide an uptick in
clouds and showers through the morning hours as it moves from
east to west. Overnight rainfall totals along windward zones have
reached at least .20 of an inch with some select leeward areas
receiving at least .01 of inch.

A 1031 mb high sitting far north of the state will continue to
drive moderate to locally breezy trade winds through the weekend
with only some slight variations as the high circulates north of
the state and fluctuates in strength. The high is expected to
weekend late over the weekend and into early next week but winds
may stay breezy locally due to a disturbance passing south of the
islands keeping the gradient tight.

As far as rainfall, expect a drying trend later this afternoon due
partially with the diurnal pattern and a drier, more stable air
mass filtering in. CIMSS precipitable water vapor imagery shows
the tail end of above normal moisture currently passing over the
state with near to below normal moisture levels upstream that
will start to filter in today. In addition 700 mb trough will
push west today while more stable conditions build in, limiting
cloud depth.

By Saturday, the GFS global models show an upper level low
dropping southward within the vicinity of the state around
Monday while the EC models has the lo lingering just west of the
state. These differences continue to create some uncertainty with
the forecast during this time. If the GFS scenario pans out it
could mean we will see an increase of shower coverage as early as
Sunday. Stay tuned for more details.


&&

.AVIATION...
A stable, moderate to breezy trade wind flow will prevail during
the next couple of days. Stable conditions will prevail, with
only limited areas of low ceilings and temporary MVFR conditions
over windward areas. Aside from afternoon clouds over Kona slopes
of the Big Island, VFR conditions will prevail.

AIRMET Tango for low-level turbulence over and downwind of
terrain will likely remain in effect during the next couple of
days. No other AIRMETS are currently in effect.


&&

.MARINE...
High pressure north and northeast of the state will keep moderate
to locally strong trade winds in place through the weekend. A
Small Craft Advisory (SCA) is now in effect for the typically
windy waters around Maui and the Big Island through 6 AM Friday.
The SCA may eventually need to be extended through the weekend.

East shore surf will hold near seasonal levels through Thursday,
then slowly lower Friday through early next week. A mix of
southeast, south and southwest swells will keep small surf
rolling into south facing shores through Monday. A slight bump in
south shore surf is possible around Tuesday or Wednesday of next
week as a slightly larger long-period southwest swell moves
through. North shore surf will remain very small through the
weekend. A nice bump in north shore surf is possible Tuesday and
Wednesday of next week as a 3 to 4 foot medium to long-period
northwest swell arrives.


&&

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


&&

$$


DISCUSSION...Almanza
AVIATION...Shigesato
MARINE...Jelsema