433
FXHW60 PHFO 110114
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
314 PM HST Thu Apr 10 2025

.SYNOPSIS...
Moderate to breezy trade winds will continue through early next
week with clouds and showers generally favoring windward and mauka
areas. Enhanced showers will be possible through tonight and
again next week as moisture from a dissipated front moves in on
the trades and a few upper level disturbances move overhead. By
Wednesday, a transition to east-southeast winds may occur and
lead to a hybrid east-southeast flow and land/sea breeze pattern.

&&

.DISCUSSION...
A plume of leftover moisture from a dissipated front continues to
stream across the state this afternoon on the moderate to breezy
trades. With the instability from the exiting upper level trough,
elevated inversion heights, and this current plume of moisture
moving across the island chain tonight, clouds and showers will
move into windward and mauka areas on the trades with a fair
amount of showers passing over the terrain to impact leeward
areas, as well.

A 1035mb surface high to the far north of the state will slide
eastward over the next couple of days, helping to maintain
moderate to breezy trades across the region - with just a slight
decline in wind speeds as compared to today. These moderate to
breezy trades will deliver clouds and showers to windward coasts
and slopes as a long band of moisture reaching far upstream moves
across portions of the island chain through the weekend. However,
mid-level ridging will temporarily build overhead as the broad
upper level trough pushes off to the east, which will help to
lower inversion heights, put a slight damper on shower activity,
and bring a more typical distribution of windward/mauka showers
tomorrow through the weekend.

Early next week, a mid-level low will move over the state from the
west with a broad upper level trough quickly following, both of
which will act to add some instability back over the area. At the
surface, the high to the far northeast will weaken in response to
a cold front moving across the eastern Pacific, allowing the
local pressure gradient to relax slightly and bring moderate to
locally breezy trades across the state. Batches of moisture caught
up in the trades will bring periodic clouds and showers that will
occasionally spill over to leeward areas at times.

Depending on the progression of a front moving through the Central
Pacific midweek next week, wind directions may begin to shift
from a more east-southeasterly direction on Wednesday, which would
allow land and sea breeze activity to expand in coverage across
the state. However, current model guidance is not in good
agreement on the pattern that far out at this time.

&&

.AVIATION...
Moderate to breezy trade winds will continue for the next few
days with the breeziest winds, both surface and aloft, expected
over the western end of the state. AIRMET Tango is now in effect
for low level mechanical turbulence to the lee of higher terrain
Kauai and Oahu.

Bands of light showers carried by the trade winds will impact
mainly windward slopes and coasts and be most active in the late
night and morning hours. AIRMET Sierra for mountain obscuration is
now in effect for north and east facing slopes of Kauai, Oahu,
Molokai, and Maui.

On the Big Island, localized sea breezes along the leeward coast
are driving cumulus development over the island`s interior.
Partial clearing expected after sunset along south and west facing
slopes of the Big Island.

&&

.MARINE...
Fresh to strong trade winds will prevail through Friday as robust
surface high pressure north of the state creeps eastward, with
most waters under a Small Craft Advisory (SCA). The pressure
gradient and resulting trades will be strongest along and just
north of a band of moisture that will linger around Kauai and
Oahu. Winds will ease slightly Friday night and Saturday as the
high moves to the east and its associated surface ridge is
weakened and displaced southward toward the state. During this
time, the SCA will likely be trimmed back to the typically windy
waters around the Big Island and Maui County. A further decrease
in trades is possible by Tuesday as the surface ridge is pushed
closer to the islands.

A series of small northwest to north-northwest swells will
produce surf below April average on northern shores through most
of the week. A mix of declining north-northwest swell and a fresh
northwest swell of around 3 to 4 feet at 12 seconds has been
observed on the local PacIOOS buoys at Hanalei and Waimea Bay,
maintaining small surf. The new swell will slowly decline Friday
afternoon through the weekend. A slightly larger northwest swell
is expected to build on Monday and decline Tuesday and Wednesday.

Strong trade winds over and upstream of the islands will produce
elevated rough surf along east facing shores through Friday. The
largest wind waves have been observed near Kauai, where the
PacIOOS buoy has been reporting over 8 feet at 8 seconds, and as
these seas peak overnight, east shore surf will be just below the
High Surf Advisory level on Kauai. The elevated seas will also
contribute to the need for a SCA around Kauai and Oahu. Surf along
eastern shores fall to near April average statewide on Saturday
and decline below average Sunday into early next week.

South shore surf will be near April average through Friday, then
decline to summertime background levels during the weekend.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
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-Maalaea Bay-Pailolo Channel-Alenuihaha
Channel-Big Island Leeward Waters-Big Island Southeast Waters.


&&

$$


DISCUSSION...Farris
AVIATION...Bedal
MARINE...Wroe