782
FXHW60 PHFO 230657
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
857 PM HST Sat Jun 22 2024

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


&&

.DISCUSSION...
The downstream pressure gradient remains tight enough across the
islands from a 1030 mb high centered approximately 950 miles
north of Oahu to maintain breezy trades well into next week. The
Hawaiian Islands remain under the stabilizing influence of the
southeasterly periphery of a mid-level ridge located northwest of
the region. Radar depicts widely scattered showers moving in on
these trades and affecting across most windward locales this
evening, especially at elevation, with the highest rainfall
focused over all windward mauka slopes this evening.

Drier air working its way into the state from the northeast on
Sunday will limit overall shower activity to just light, isolated
showers confined to windward mauka regions. Slightly higher mid-
level moisture advecting in Monday may increase shower coverage
and produce a few hundredths of an inch more rain over those
communities that typically receive more rain during normal trade
flow. Little to no movement of the lower and upper ridge planted
north of the islands through the middle of next week ensures daily
breezy trade flow 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
may weaken the pressure gradient enough to subtly suppress trade
flow to more gentle magnitudes, although easterlies will still
remain breezy along better exposed windward ridge lines and within
more east-to-west orientated valleys. Lowering mid to upper
heights, with periodic ribbons of higher moisture, will increase
shower frequency and areal coverage later in the week. The
possible development of an upper level disturbance east or
northeast of the islands will 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 within 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 the early Sunday morning hours.

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...
Surface high pressure, centered around 850 nm north of the state,
will remain nearly stationary over the next several days and help
generate strong easterly trades. A Small Craft Advisory will
remain in effect for all local waters through Monday night. Trades
are expected to decrease slightly Tuesday through midweek as the
aforementioned surface high drifts northeast away from the
islands.

Surf along east-facing shores will remain rough and choppy through
early next week due to the strong trades locally and upstream of
the state. A gradual downward trend is expected Tuesday through
midweek.

Surf along south-facing shores remains slightly elevated tonight
into Sunday as a small medium to long period south swell moves
through. This should be short-lived, with a downward trend
expected early next week. 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 next week.

Surf along north-facing shores will remain nearly flat on Sunday.
A small, medium period, northwest swell will bring tiny surf to
north-facing shores by early next week.

&&

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


&&

$$


DISCUSSION...Blood
AVIATION...Gibbs
MARINE...Thomas