634
FXHW60 PHFO 261946
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
946 AM HST Sun May 26 2024

.SYNOPSIS...
Broad high pressure north and northeast of the state will
maintain moderate to locally breezy easterly trade winds through
the week. Showers will mainly favor windward and mauka areas, with
areas of high clouds passing overhead at times.

&&

.DISCUSSION...
At the surface, broad high pressure far north of the islands is
driving moderate to locally breezy trade winds across the state.
Meanwhile, satellite imagery shows showers and thunderstorms with
a surface trough and its attendant low aloft roughly 600 nm west
of Kauai. This is causing the trades to veer slightly more east-
southeast than usual, particularly across the western islands.
Showers favoring windward locations have remained fairly light
this morning, though some areas of Kauai did receive meaningful
rainfall overnight.

Little change is expected over the next few days as high pressure
gradually strengthens north/northwest of the islands and the
trough and upper low west of the state remains nearly stationary
through Tuesday. Shallow moisture embedded within the trades will
produce some windward and mauka showers at times, particularly
during the overnight through early morning hours each day.
Additionally, expect spotty afternoon and evening showers, some
briefly heavy, across leeward portions of the Big Island. The
trough`s proximity to the western end of the state will weaken the
inversion at times near Kauai and could enhance shower activity
there, similar to last night. However, guidance is in agreement
that the trough will remain far enough west of the main Hawaiian
Islands to have little impact to local weather otherwise.

The surface high will settle far northeast of the state and hold
into Friday, while the surface trough lingers west of the islands
and produces breezy easterly trade winds. The nearby upper-level
trough will weaken around mid-week, leading to greater stability
and supporting a more typical trade shower pattern favoring
windward and mauka areas.

&&

.AVIATION...
A fairly stable pattern will remain over the state over the next
few days with some passing high clouds overhead. Moisture embedded
within the trade flow will allow for SHRA over windward and mauka
areas. VFR conds should prevail over most locations, with MVFR
conds possible in any SHRA.

AIRMET Sierra is in effect for mtn obsc for, windward Big Island
and NE through SE portions of Kauai. Conditions are expected to
improve later this morning, but conditions could return tonight
especially over windward Big Island.

AIRMET Tango remains in effect for moderate low-level turb
downwind of island terrain. This AIRMET will likely remain in
effect through much of this week.

A weak shortwave trough passing just west of the state on Monday
should bring an increase of mid level clouds around Kauai Monday
afternoon and evening. Although low probability, there is a chance
for some light icing between 160 and FL250 Monday afternoon
through Monday night.

&&

.MARINE...
Moderate to strong easterly trades will continue through the
week as the surface ridge remains positioned north of the state.
The strongest winds are expected over the windier waters around
Maui County and the Big Island, supporting the Small Craft
Advisory. The lightest winds are anticipated over the Kauai
waters, fluctuating between east and east-southeast over the next
few days due to a persistent surface trough to the west.

Surf along exposed south-facing shores will remain small
throughout much of the week, mainly due to a combination of
background south-southwest and southeast swell energy. An upward
trend is expected from Friday through the first week of June due
to an active pattern unfolding within our swell window near New
Zealand.

Altimeter and ASCAT passes over the past 24 hours reflected the
potential for next weekend, showing a broad swath of gales with
seas up to 30 feet focused at the state within the 190-200 degree
directional bands. This will mark the beginning of a long-lived
event with additional reinforcements expected within the same area
over the next several days.

Surf along exposed east-facing shores will remain small and
choppy throughout the week as the trades persist.

Surf along exposed north-facing shores may increase slightly later
today through Monday due to a small, medium-period northwest
swell expected. Otherwise, summertime conditions are anticipated
with minimal surf expected this week.

&&

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

&&

$$

DISCUSSION...Vaughan
AVIATION...Kino
MARINE...JVC