392
FXHW60 PHFO 271913
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
913 AM HST Thu Mar 27 2025

.SYNOPSIS...
A mostly dry and stable east to southeast flow will prevail
through the weekend. Limited showers will favor windward and
southeast facing slopes, and only a few will develop over
interior and leeward areas each afternoon. Rain chances may
increase early next week, mainly over the western end of the
state, as deep low pressure west of the state potentially draws
moisture over the islands.

&&

.DISCUSSION...
A stable east to southeast flow will continue to produce limited
showers. A surface ridge sitting about 200 miles north of Kauai
is driving moderate easterly trade winds around the Big Island and
mainly gentle southeast winds from Maui to Kauai. This has led to
modest showers over east and southeast slopes of the Big Island
and east Maui, while lingering land breezes and mostly dry
conditions prevail from west Maui to Kauai this morning. Expect
showers to diminish over east and southeast Big Island and east
Maui over the next few hours, and daytime sea breezes will produce
clouds and spotty showers over leeward terrain and interior areas
this afternoon. A building upper level ridge over the islands
will keep stable conditions in place and lead to generally light
shower activity.

Little change is expected through the weekend. A cutoff low will
form about 1100 miles northwest of Kauai on Saturday and deepen
through Sunday. This will keep the subtropical ridge in place
roughly 200 miles north of Kauai, maintaining the east to
southeast flow, and the ridge aloft will support stable
conditions. Aside from a small batch of moisture that may graze
Kauai tomorrow, expect a continuation of modest showers over east
and southeast Big Island and east Maui, with a land and sea breeze
regime elsewhere.

The ongoing volcanic emissions from Kilauea have proven difficult
to track. Volcanic haze (vog) concentrations will obviously be
highest over southeast and leeward Big Island, but air quality
observations and visuals do not suggest that significant vog has
been transported to the rest of the island chain just yet. The
University of Hawaii VMAP model suggests that some vog will reach
Maui through Kauai over the next 24 hours, but shifting winds
above the surface may lead to reduced vog on Sunday.

Rainfall chances trend higher next week. Significant differences
in the GFS and ECMWF guidance persist, but recent operational
runs and their ensemble solutions all keep the deepest moisture
associated with the above mentioned low west of the state.
However, increases in shower activity and southerly winds are
possible over mainly the western end of the island chain through
Wednesday.

&&

.AVIATION...
Light to moderate southeasterly winds will produce land and sea
breezes over all islands. Brief showers are possible, mostly VFR
conditions will prevail.

East to southeast slopes of the Big Island and Maui may see
periods of MVFR conditions in low clouds and showers with land
breezes tonight.

AIRMET Sierra is in effect for mountain obscuration for the Big
Island. Otherwise, No AIRMETs are currently in effect.

&&

.MARINE...
No marine headlines are expected through the weekend, with seas
of about 3 to 6 feet anticipated.

A surface ridge will remain near or just N of the islands through
the weekend, with light to moderate E-SE winds prevailing. Diurnal
land and sea breezes will dominate the flow over nearshore waters
sheltered from the large-scale flow. Early next week, deep-layer
low pressure far NW of the islands may bring increased S-SW winds.

The large scale pattern will be supportive for the development of
relatively small N-NE swells for the islands over the next week or
so. In the short term, the fetch associated with a storm-force low
near WA/OR will send a NNE swell toward the islands from later
today into Sunday, with the swell likely peaking ~4 feet 12
seconds on Friday. A small WNW swell may also arrive over the
weekend. More medium-period N swell is anticipated next week.
Small, long-period SSW swells are expected to provide small surf
to S facing shores into next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Wroe
AVIATION...Shigesato
MARINE...Walsh/Kino