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000
FXHW60 PHFO 190647
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
847 PM HST Thu Apr 18 2024

.SYNOPSIS...
Mostly dry trade wind conditions will prevail through next week.
Breezy northeast trade winds will briefly weaken over the weekend,
then become breezy again out of the east early next week. Clouds
and brief showers will favor windward and mauka locations, mainly
during the overnight through early morning hours, as areas of
moisture move through periodically.


&&

.DISCUSSION...
No changes to the forecast this evening, and not expecting any
significant changes with the morning package. High pressure far to
the north-northwest of the state will be drifting to the east,
with a ridge of high pressure remaining north of the region. This
will maintain a trade wind pattern into the middle to end of next
week.

Lingering moisture from an old frontal system, and enhanced by an
upper level trough moving east away from the region, is moving
down the island chain this evening. High resolution models show
this band sagging southward overnight, bringing some additional
showers to windward Maui County, before diminishing Friday.

Expect a return to a drier trade wind pattern behind this band.
Mid and upper level ridging will help to maintain that drier trade
wind pattern into next week. Clouds and showers will be riding in
on the trade wind flow, and remain focused over the typical
windward sides of the islands. Those showers will be concentrated
during the overnight and morning hours. Clouds and limited showers
are also expected over the west slopes of the Big Island mainly
during the afternoon and evening hours.

The breezy trades will hold Friday, then ease into the light to
moderate range over the weekend as a weakness forms in the surface
ridge due to a low passing far to the north. The southern extent
of a mid- to upper-level trough associated with this system will
pass near the islands to the north late Friday into the weekend,
which could support a slight increase in windward shower coverage
during the overnight/early mornings. Rising upper heights along
with a strengthening surface ridge to the north will support dry
conditions prevailing early next week with breezy easterly trades
returning.


&&

.AVIATION...
Moderate trade winds will remain in place through tomorrow as high
pressure remains north of the islands. A band of low clouds and
showers will continue bringing MVFR clouds and showers to Kauai
and Oahu tonight and will likely spread down the island chain and
affect Maui County later tonight into tomorrow morning. An improvement
in conditions can then be expected tomorrow by late morning.
Trade wind showers could then increase again by tomorrow evening.


AIRMET Sierra for tempo mountain obscuration remains in effect
for Kauai and Oahu due to the cloud band.


&&

.MARINE...
A series of surface highs will build and pass north of the state
through early next week. Moderate to fresh trades will persist
through Friday weakening slightly over the weekend. A Small Craft
Advisory (SCA) is in effect through the day Friday for the typical
windy zones around Maui County and the Big Island. Trades will
become fresh to locally strong early next week.

Moderate surf along south facing shores will hold through tonight
than slightly decline Friday. A series of small, medium period
swells will persist through the weekend keeping south facing
shores from going flat. Small, short- period north swell will
continue into into the weekend. A larger moderate medium period
north swell reinforcement will arrive early Sunday. Surf along
east facing shores will remain small but can expect a minor boost
as winds pick up Monday.


&&

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


&&

$$


DISCUSSION...M Ballard
AVIATION...Tsamous
MARINE...Shigesato