209
FXHW60 PHFO 100627
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
827 PM HST Wed Oct 9 2024

.SYNOPSIS...
Moderate northeast trades will weaken over the next several days
in response to a couple fronts north of the islands disrupting the
trade wind flow. A trough moving in from the east will increase
clouds and showers into Friday. Some strengthening of the trades
is expected early next week.


&&

.DISCUSSION...
Clouds associated with a weakening surface trough are moving into
the coastal waters to the east of the Big Island this evening.
Expecting an uptick in clouds and showers over the Big Island
overnight, and into Thursday as as result. The northern portion of
the trough will reach the smaller islands a little later, likely
on Thursday. Although the trough will be weakening, some clouds
and showers will move into the windward and mauka areas of the
smaller islands. Water vapor imagery shows the expected upper
level low about 500 miles to the west-northwest of Kauai. This
upper level feature will continue to move away from the islands
and is not expected to have much of an influence on the shower
activity. Some thin high clouds are moving over the islands from
the south on the east side of the upper level low. An upper level
ridge building over the islands will help to stabilize the
airmass Friday.

The surface trough is helping to keep winds at light to moderate
levels. Expect winds to weaken a bit over the next day or two as
the trough moves over the islands. A couple of fronts passing far
north of the islands will help to maintain light to moderate
trades winds into the weekend. Heading into the new week, high
pressure will move in behind the fronts to the north of the
islands, allowing trades to rebound to moderate to locally breezy
levels.


&&

.AVIATION...

Expect moderate trades through the rest of the week. SHRA and low
cigs will bring brief MVFR conds to windward and mauka areas. VFR
should prevail elsewhere.

No AIRMETs are currently in effect.


&&

.MARINE...

A ridge of surface high pressure far northwest of the state will
remain nearly stationary through Thursday and maintain moderate to
locally fresh trades across the local waters. Late Thursday into
the weekend, a weak cold front will drop southward, weaken the
pressure gradient, and allow local winds to gradually trend down.
Small Craft Advisory conditions may develop early next week as a
high rebuilds north of the state and moderate to locally strong
trade winds return.

Evening nearshore buoy data still indicates the presence of a 4
to 5 foot, 11 to 14 second, north northwest (340 degree) swell,
which will continue to produce small surf along north facing
shores. This swell is expected to slowly subside through Friday.
However, a similar size north swell will reinforce surf heights
this weekend. The next significant northerly swell (350 degree)
will likely arrive late Sunday into early next week and may be
large enough to produce High Surf Advisory level conditions along
north facing shores.

A small south southwest (180-200 degree) swell, will slowly fade
through Thursday morning producing small to tiny surf along south
facing shores. Long period forerunners of the next small south
swell is poised to trickle in mid- day Thursday and will reinforce
south shore surf Thursday night into Friday before gradually
trending down over the weekend. Surf along west- facing shores
will be influenced by a mixture of both north northwest and south
southwest swells. Thus, expect western exposures to remain
slightly elevated as well. Expect below normal small east- facing
shore chop over the next several days as trade wind flow remains
relatively weak locally and upstream.



&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$


DISCUSSION...M Ballard
AVIATION...Walsh
MARINE...Thomas