High Surf Warning 6, NWS Honolulu, HI

Area Forecast Discussion
National Weather Service Honolulu HI
357 PM HST Sun Mar 23 2025

.SYNOPSIS...
Light to occasionally moderate east to southeasterly winds are
expected to continue through most of the week and into next
weekend, with only slight variations in speed and direction. In
this flow, clouds and showers will favor windward areas overnight
and leeward and interior areas in the afternoon where sea breezes
develop. Overall, shower activity will be limited. However,
moisture from a front expected to stall just north of Kauai may
bring an up tick in shower to the western end of the state tonight
into tomorrow and an upper level disturbance may bring another
uptick in showers midweek.

&&

.DISCUSSION...
This afternoon's radar, satellite imagery and surface
observations show that sea breezes are in full swing with clouds
and isolated showers building over island interiors. This activity
will continue into the early evening hours.

The approach of a cold front from the northwest will keep the
ridge axis shifted south of its usual position and nearly atop of
the island chain, maintaining a light east-southeasterly flow
across the state through tomorrow. The cold front will stall north
of the state tonight, along with the bulk of its moisture.
However, if the front manages to sag a bit further south than what
current model guidance is showing, its moisture field could bring
a slight bump in shower activity to the western end of the state
tonight into tomorrow. Otherwise, in this lighter flow, the east-
southeasterly winds will help to focus low clouds and showers over
windward areas, particularly overnight, while land breezes will
help to bring clearing to leeward areas by morning. Sea breezes
will then bring cloud buildups and a few showers to leeward and
interior areas during the day. Overall, shower activity will be
limited as mid-level ridging tries to build overhead, increasing
atmospheric stability, and drier air continues to filter in from
the east.

This pattern is expected to persist through most of the week and
into next weekend as a progressive pattern to the north keeps the
surface ridge relegated south of its usual position and light to
moderate east to southeasterly winds persist across the state. A
possible deviation from this pattern may occur Tuesday into
Wednesday as a perturbation in the flow aloft moves overhead and
increases atmospheric instability, which may lead to a slight
uptick in shower activity as pockets of moisture move in on the
east to southeasterly flow. Then models show reasonable agreement
on mid- level ridging building back overhead for the latter part
of the week and into the weekend, which will help to suppress
shower activity once again.

&&

.AVIATION...
Light east-southeast winds through Monday as a cold front passes
north of the area. Daytime sea breezes will continue through
sunset that will bring interior clouds with with isolated showers,
followed by clearing tonight with land breezes.

AIRMET Sierra is posted for tempo mountain obscurations over Kauai
above 2500 feet. These clouds will dissipate around sunset and the
AIRMET will be dropped. No other AIRMETs are expected through
Monday morning.

&&

.MARINE...
Moderate to locally fresh east southeast winds will continue to
ease through the day in response to a surface ridge weakening and
settling south into the area as a front approaches. This front is
expected to stall just north of Kauai later tonight into Monday,
resulting in light to locally moderate east-southeast winds across
the area through Monday, with the lightest winds near Kauai. Winds
will then increase slightly and shift out of the southeast across
much of the island chain through Tuesday night, as low pressure
develops far northwest of the state. Little change is expected in
this pattern through Friday.

A long-period northwest (305-325 degrees) swell is quickly building
down the island chain today, as reflected in the nearshore buoy obs,
and will peak tonight through early Monday. A High Surf Advisory
(HSA) remains in effect for most north and west facing shores of
the smaller islands, but have extended it in time through Monday
night. Surf heights will near warning levels through the peak.
Current projections keep surf heights just under warning level,
but will continue to monitor in case a High Surf Warning (and
adding an HSA to exposed west facing shores of the Big Island) is
needed. A Small Craft Advisory has been issued for exposed waters
due to seas expected to exceed 10 feet with this swell. The swell
will gradually ease Tuesday through midweek as it shifts out of
the north.

Choppy east shore surf, already below seasonal averages, will drop
further through the rest of the weekend and remain small through
the upcoming week as wind speeds remain on the lighter side. South
shore surf will remain seasonably small, though a small bump is
possible around midweek.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 AM HST Tuesday for Niihau-Kauai
Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kauai
North-Molokai Windward-Molokai North-Molokai West-Maui Central
Valley North-Windward Haleakala.

Small Craft Advisory until 6 PM HST Monday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Kaiwi Channel-Maui County Windward Waters.

&&

DISCUSSION...Farris
AVIATION...Foster
MARINE...TS