888
FXHW60 PHFO 240142
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
342 PM HST Sun Jun 23 2024

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

&&

.DISCUSSION...
Breezy to locally windy trade winds continue this afternoon as a
1031 mb surface high remains approximately 925 miles north of
Kauai. Stable conditions also continue as mid-level ridging
remains in place to the northwest of the state. Radar and
satellite imagery show much drier conditions compared to
yesterday with widely scattered weak trade showers moving across
the islands. Expect these conditions to continue tonight with
showers favoring windward coasts and slopes.

The biggest change to the forecast this afternoon has been the
issuance of a Wind Advisory for the Big Island Summits. Obs from
the Gemini Observatory peaked around 40 mph this afternoon, with
guidance showing the potential for gusts over 60 mph possible late
tonight into Monday. Expect winds to peak Monday morning before
trending downward in the afternoon.

Otherwise, the strong surface high will remain to our north
through Monday which will maintain our breezy trade wind
conditions. A stable and rather typical summertime rainfall
pattern will prevail with modest rainfall possible over windward
coast and slopes. Aside from some brief afternoon showers over
Kona slopes of the Big Island, leeward areas will be mostly dry.

Trades look to then weaken slightly on Tuesday as the high to the
north weakens, with passing showers over windward coasts and
slopes through the middle of the week. Guidance continues to show
an uptick in shower activity possible later this week and into the
upcoming weekend as an upper-level disturbance develops northeast
of the islands. This increased instability combined with bands of
moisture embedded in the trade wind flow 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 each day.

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

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...
Afternoon ASCAT imagery supports dropping the Small Craft Advisory
(SCA) for the western half of the area. Otherwise, fresh to strong
easterly trades still expected to continue through early this week
and the SCA remains in effect for remaining waters through Monday.
Trades weaken slightly Tuesday into mid-week.

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...
Wind Advisory until 6 PM HST Monday for Big Island Summits.

Small Craft Advisory until 6 PM HST Monday for Maui County
Leeward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha Channel-
Big Island Windward Waters-Big Island Leeward Waters-Big Island
Southeast Waters.

&&

$$

DISCUSSION...Ahue
AVIATION...Powell
MARINE...JVC