116
FXHW60 PHFO 231924
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
924 AM HST Sun Jun 23 2024

.SYNOPSIS...
High pressure north of the state will maintain breezy trade winds
the next few days. Showers will primarily favor windward coasts
and slopes. Trades will weaken slightly around the middle of the
week, with a possible uptick in shower activity late in the week.


&&

.DISCUSSION...
The downstream pressure gradient from a 1030 mb high centered
approximately 950 miles north of Kauai remains tight enough across
the island chain to continue breezy trades the next few days. The
Hawaiian Islands will remain under the stabilizing influence of
mid-level ridging as the area falls along the southeasterly
periphery of the 700 mb ridge positioned to the northwest. Water
vapor imagery continues to show a drier air mass over the islands
this morning with widely scattered weak trade showers.

While morning sounding precipitable waters fall in-line with late
June climatology numbers (1.3-1.4 inch pwats), mid to upper level
northeasterly drier air advecting into the state will limit
overall shower activity today with light, isolated showers
primarily confined to windward coasts and slopes. Slightly higher
mid- level moisture advecting in Monday, along with a 6-7 kft
fairly saturated layer, may be enough to increase shower coverage
and produce a few hundredths more rain in those communities that
typically stay wet during a normal trade flow pattern. Little to
no movement of the lower and upper ridge planted north of the
islands through Tuesday ensures breezy trades under partly to
mostly cloudy windward skies...mostly to partly sunny leeward
skies. High pressure at all levels begins to transition east
during the latter half of the week. This will weaken the lower
level pressure gradient enough to subtly suppress trade flow to
more gentle magnitudes, although easterlies will still remain
breezy along ridge lines and within more east-to-west orientated
valleys. Lowering mid to upper heights, with periodic ribbons of
higher moisture passing to the west, will increase shower
frequency and areal coverage later in the week. Higher confidence
in the development of an upper level disturbance east northeast of
the islands will certainly boost weekend rain chances as we close
out the month of June.


&&

.AVIATION...
Breezy to locally windy trades will continue through Monday.
Showery cloud bands embedded in the trade flow will produce
periods of MVFR conditions across windward/mauka areas of each
island, particularly through the overnight and early morning hours
each day. Conditions will improve through the late morning and
afternoon periods.

AIRMET Sierra remains in effect for tempo mountain obscuration
for windward slopes of most islands, which will likely continue
through today.

AIRMET Tango remains in effect for mod low-level turb over and
downwind of island terrain due to the breezy trade winds. This
AIRMET will continue through Monday.


&&

.MARINE...
Strong easterly trades continue through early this week, and the
Small Craft Advisory remains in effect for all waters through
Monday night. Trades then weaken slightly Tuesday into midweek.

Surf along east-facing shores will remain rough and choppy through
Monday followed by a gradual downward trend during mid-week as
trades weaken slightly.

Expect slightly elevated surf near or slightly below seasonal
norms along south facing shores through Tuesday as a small,
medium to long period, south swell moves through. The swell has
already shown up on the Barbers Point Buoy with energy in the
14-16 second bands. However, this should be short-lived, with a
downward trend expected by Tuesday night. Despite a blocking high
that has set up over our typical swell window southeast of New
Zealand, a gale has formed northeast of this high with the head of
the fetch aimed at the islands within the 180 to 200-degree
directional band. Given the shorter travel distance, surf
associated with this source should trend up late this week.

Nearly flat conditions along north facing shores today. A small,
medium period, northwest swell will bring tiny surf to north
facing shores late Monday through mid week.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Monday for all Hawaiian
waters-


&&

$$


DISCUSSION...Ahue/Blood
AVIATION...
MARINE...JVC