Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 05/30/2026 05:24:00 AM UTC

                        
403
FXHW60 PHFO 291924
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
924 AM HST Fri May 29 2026

.SYNOPSIS...
Breezy trades will gradually weaken through the weekend as a
stout low pressure system developing to the far north disrupts the
surface ridge extending over the islands. Clouds and showers will
favor windward and mauka areas today, then the focus shifts to
sea breezes each afternoon over the weekend. Early next week,
increasing moisture will move up the island chain from the
southeast, increasing rain chances for the eastern end of the
state Monday night through Tuesday night. Moderate to locally
breezy trades are expected to return shortly thereafter for the
remainder of the forecast period.

&&

.SHORT TERM UPDATE...
Radar and satellite look much the same as yesterday, with isolated
showers mainly windward and mauka. A few showers were progressing
past the Koolau`s and making it into Honolulu, but this should
diminish this afternoon. The forecast is in good shape and no
changes will be made at this time.

&&

.PREV DISCUSSION...
Issued at 325 AM HST Fri May 29 2026
A strong surface ridge positioned north of the state will remain
the primary driver of weather conditions across the Hawaiian
Islands today. This pattern will continue to support moderate to
locally breezy trades and maintains periodic shower activity
mainly focused over windward and mauka areas. In addition, a weak
upper-level trough quickly moving west to east across the state
this morning will temporarily weaken the low-level inversion,
allowing for a slight increase in moisture, cloud cover, and
shower activity through the morning hours.

Trades will begin to weaken shortly thereafter as a broad area of
low pressure develops southward from the Aleutian Islands. This
system will erode the surface ridge and weaken the local pressure
gradient, leading to lighter winds and the potential for localized
land and sea breeze development through the weekend and into
early next week. As a result, interior and leeward areas may
experience increased afternoon cloud and shower development,
followed by overnight clearing.

Model guidance indicate that moisture levels will gradually
increase between Monday night and Wednesday as a large plume of
tropical moisture lifts northwestward across the island chain
from the southeast. Meanwhile, ridging will begin to rebuild over
the region as the low pressure system lifts northward into the
Gulf of Alaska, allowing trades to strengthen once again. This
return to a more typical trade pattern will favor isolated to
locally scattered showers, mainly favoring windward and mauka
areas, through the remainder of the forecast period.

&&

.AVIATION...
Trade wind pattern continues today with isolated showers in
windward areas. Localized MVFR windward and mauka, but improving
conditions during the day. VFR prevails.

AIRMET Sierra is in effect for mountain obscuration on Kauai Oahu
and the Big Island, but will likely be cancelled by 20Z as
conditions improve but may be needed again tonight.

And AIRMET Tango is in effect for moderate turbulence downwind of
mountain areas which will continue today.
&&

.MARINE...
Fresh to strong trade winds will persist today as the subtropical
ridge remains strong north of the state. As such, the Small Craft
Advisory is in effect through this afternoon for the windier
waters around Maui and the Big Island. Thereafter, guidance
depicts the ridge beginning to weaken in response to broad low
pressure developing roughly 1,500 nautical miles to the north near
the Aleutian Islands this weekend through early next week. This
will translate to local trades easing into the light to moderate
range, likely giving way to localized land and sea breezes near
the coasts late this weekend through early next week. A return of
moderate to fresh easterly trades is likely by midweek as the
ridge strengthens.

An active pattern is in store for surf along south-facing shores
as we head into June due to a series of recent gale- to storm-
force lows passing through our swell window near New Zealand over
the past week. Expect surf to gradually build today as forerunners
from a long-period south-southwest swell arrive while the current
medium-period south swell fades out. Our buoys are already
reflecting this new source with energy registering in the 20-23
second bands this morning. Surf heights will likely reach the
advisory level by tonight, with the swell becoming fully
established by Saturday. Heights will hover near the advisory
level through the weekend. As the swell gradually begins to ease
early next week, long-period forerunners from the next south-
southwest swell are expected to arrive. Heights may briefly dip
below the advisory level Monday night, but as the next swell fills
in, surf will likely return to the advisory level Tuesday through
midweek as it peaks. A gradual downward trend is then expected
through the second half of next week.

A combination of advisory-level surf this weekend and water
levels hovering above predicted levels could lead to some wave
runup issues, with water sweeping across areas of beaches that
typically remain dry. Water levels will steadily lower each day
early next week as the next large south swell arrives.

The current small northwest swell will slowly lower through
Saturday before fading on Sunday. A small north swell will likely
produce surf near seasonal averages along north-facing shores from
late Tuesday or Wednesday into Thursday.

Expect surf along east-facing shores to remain near seasonal
averages today, then gradually decline through early next week as
trade winds ease. A slight increase is possible Tuesday and
Wednesday due to a combination of rebuilding trade winds and a
wrapping north swell.

&&

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


&&

$$

SHORT TERM UPDATE...Parker
DISCUSSION...Pierce/Pechacek
AVIATION...JVC
MARINE...Farris