High Surf in Hawaii, March 14 to 15, 2024

Area Forecast Discussion
National Weather Service Honolulu HI
342 AM HST Thu Mar 14 2024

.SYNOPSIS...

A weak cold front will continue to make its way down the island
chain before dissipating near the Big Island later today. A band
of moisture riding ahead of the front has increase showers across
the central islands. Some moisture may linger near the eastern
end of the state through Friday, but otherwise, moderate to
locally breezy northeasterly winds will usher in cooler and drier
weather through the weekend.

&&

.DISCUSSION...

Latest sounding data from Lihue shows an inversion has set up
over Kauai around 7 kft and precipitable water values have dropped
about half of an inch since the Tuesday 00Z sounding. The Hilo
sounding shows an elevated inversion around 12 kft and about a
tenth of an inch in precipitable water drop than the 00Z Tuesday
sounding. This along with the infrared and CIMSS satellite
precipitable water imagery confirms the front has moved through
Kauai and is weakening between Oahu and Maui County. Radar imagery
continues to show scattered showers over Maui County. Rainfall
rates appear to have become more light to moderate in nature as
the upper and mid level trough has weakened and moved east of the
state. Weak northerly winds appear to be bleeding out ahead of the
main frontal band allowing for hybrid northerly winds converging
with overnight land breezes, especially over Maui County. Moisture
will linger around Maui County and the Big Island today into
Friday, producing occasional showers that will generally favor
windward and mauka locations.

Moderate to locally breezy northerly flow will continue to fill
in across the islands from west to east over the next few days
bringing drier and slightly cooler temperatures. Dewpoints will
reach in the mid to upper 50's for the smaller islands while Big
Island coastal area will reach in the low 60's over the weekend.
Max high temperatures will be in the upper 70's to low 80's.

Forecast is on track with mid and upper level ridging building
north of the islands today and Friday, increasing stability as a
weak surface high builds north of the state. Northeast winds will
become moderate Friday through the weekend as they shift more
easterly. Expect a return to a drier trade wind pattern this
weekend, with a series of progressive low pressure systems and
fronts moving eastward well north of the main Hawaiian Islands
into next week.

&&

.AVIATION...
Periods of showers and MVFR conditions will continue today as a
weak cold front moves through the Hawaiian Islands. Light
northerly winds will blow across the region. Clouds and showers
will favor northern and western sections of each island.

AIRMET Sierra is in effect for tempo mountain obscuration above
2,000 feet for Kauai, Oahu, Molokai, Lanai and Maui. This AIRMET
will likely decrease in coverage later this morning.

&&

.MARINE...
A weakening cold front will push down the island chain today and
tonight, with moderate to fresh northerly winds developing across
the waters. Winds will shift northeast at moderate to fresh
levels Friday as a weak high builds northwest of the state. Winds
will ease into the light to moderate range and shift to a more
typical east-northeasterly trade wind direction over the weekend
into early next week as the weak high passes by to the north of
the state. Winds are expected to remain mostly below Small Craft
Advisory (SCA) thresholds through early next week. SCA level seas
will impact portions of the marine area as a large northwest
swell moves through today through Friday night.

Long period forerunners from an incoming large northwest swell
have reached the smaller islands early this morning, while buoys
51001 and 51101 northwest of Kauai have risen quite a bit
overnight. This swell will rapidly build from northwest to
southeast down the island chain this morning, bringing warning
level surf to north and west facing shores of the smaller islands
through Friday. Surf may reach advisory levels along the west
facing shores of the Big Island late tonight through Friday night
as well. This large swell will decline Friday night and Saturday.
A reinforcing northwest swell should arrive Saturday night,
keeping some moderate sized surf in place along north and west
facing shores through early next week. Another long period
northwest swell reinforcement may push surf up to advisory levels
Wednesday.

South shore surf will remain small through Saturday. A south
swell arriving Sunday should produce a slight increase in the surf
that is expected to persist through Monday. East shore surf will
trend down during the next couple days, then remain well below
normal through early next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Warning until 6 PM HST Friday 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 Friday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters.

&&

DISCUSSION...Almanza
AVIATION...Bohlin
MARINE...Jelsema