475
FXHW60 PHFO 261343
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
343 AM HST Wed Jun 26 2024

.SYNOPSIS...
A stable trade wind pattern will persist through much of the week
with breezy to locally windy trades. Periodic light showers will
focus over windward and mauka areas during this time. An increase
in shower activity and isolated thunderstorms will be possible
over portions of the state from Friday into the weekend as an
upper-level disturbance approaches and moves over the region.

&&

.DISCUSSION...
The 1027 mb surface high remains approximately 850 miles north-
northwest of the islands this morning. Stable conditions continue
across the region with the base of the inversion around 5000 ft.
12Z soundings from Hilo and Lihue continue to show limited low-
level moisture with dry air aloft. Radar and satellite imagery
continue to show mainly dry conditions across the state, with
periodic light showers over the typical windward and mauka areas.
Expect mainly dry conditions to continue today with passing
showers under breezy to locally windy trades.

High pressure to the north is expected to weaken slightly over
the next couple of days. This should relax our local pressure
gradient a bit, but winds will remain breezy to locally windy
through much of the week. Impulses of moisture embedded in the
trade wind flow will continue to favor windward and mauka areas,
though rainfall accumulation will be limited. Aside from some
brief afternoon and evening showers over Kona slopes of the Big
Island, leeward areas will remain mostly dry.

Conditions start to change near the end of this week and into the
weekend as guidance continues to show an upper-level disturbance
moving across the islands from east to west. This disturbance will
help to increase instability and enhance our trade wind showers,
particularly on Saturday night. Isolated thunderstorms continue to
be a possibility over the slopes of the Big Island on Friday and
Saturday afternoons and over the western end of the state on
Saturday and Sunday as temperatures aloft cool. However, with
precipitable water forecast to be below seasonal normals of 1.3
inches, the amount of moisture available will continue to be a
limiting factor. Will continue to evaluate thunder chances over
the next several model runs, with further refinement in timing
and areal coverage expected. Otherwise, enhanced trade wind
showers look to continue into Monday. Conditions return to a more
typical summertime trade wind pattern by early next week.

&&

.AVIATION...
Breezy trade winds will persist across the island chain through
Thursday. Showers and low clouds riding in on these trades will
bring brief periods of MVFR conditions over windward and mauka
locations. Otherwise, VFR conditions will prevail.

AIRMET Tango remains in effect for moderate low-level turbulence
over and downwind of island terrain due to breezy trade winds
under the tradewind inversion.

No other AIRMETs are in effect at this time. However, AIRMET
Sierra for tempo mountain obscuration may be needed again if
shower coverage increases.

&&

.MARINE...
High pressure will remain north of the state over the next couple
of days. Moderate to locally strong easterly trades will persist
through Thursday then weaken slightly to the gentle to fresh range
as the high slowly weakens and shifts eastward Thursday night
through weekend. A Small Craft Advisory (SCA) for the typically
windier waters around Maui County and the Big Island remains in
effect through Thursday afternoon. The SCA may be dropped as early
as Thursday night into Saturday as the high weakens. An upper
level low may bring isolated thunderstorms over the weekend which
could imply locally higher winds and seas. SCA conditions may
return to the typically windy waters Sunday into early next week
as the high northeast of the state strengthens and a new high
builds north of the state from the northwest.

Surf along east-facing shores will gradually ease through the week
as the winds locally and upstream trend down.

A small, medium-period, south swell will slowly trend down today
and become more inconsistent. Another small, medium- to long-
period south swell will fill in tonight, before peaking Thursday
night then gradually ease into the weekend maintaining near to
below average surf along south facing shores.

Surf along north facing shores will be minimal today. A small,
medium period, northwest swell could fill in later today, before
peaking Thursday night which could provide a small bump along
north facing shores through the rest of the week.

&&

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

&&

$$

DISCUSSION...Ahue
AVIATION...Shigesato/Powell
MARINE...Almanza