235
FXHW60 PHFO 270127
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
327 PM 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...
Broad high pressure far north of the islands is driving moderate
to locally breezy trade winds across the state. Regional infrared
satellite imagery shows an area of showers and thunderstorms
roughly 550 nm west of Kauai associated with a surface trough and
its attendant low aloft. This feature is also causing local trades
to veer slightly more east-southeasterly than usual, particularly
across the western islands. Locally, afternoon soundings from
Lihue and Hilo show mostly stable conditions, and latest radar
imagery shows only a few light showers around the state.

Through Tuesday, little change is expected in the overall pattern
as high pressure gradually strengthens to the north/northwest and
the trough and upper low west of the state remain nearly
stationary. 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.

For the rest of the week, 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. 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 for mtn obsc could return tonight across windward
areas especially over Big Island as a plume of moisture moves in
late tonight.

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 36 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.

For north-facing exposures, expect summertime conditions with
minimal surf 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