985
FXHW60 PHFO 280155
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
355 PM HST Thu Jun 27 2024

.SYNOPSIS...
Moderate trade winds will prevail through the weekend, strengthening
somewhat early next week. Clouds and showers will favor windward
areas, with the potential for increased shower coverage and
intensity this weekend as an upper-level low passes just north of
the islands. The low will also bring the potential for isolated
thunderstorms, especially over interior Big Island during the
afternoons.

&&

.DISCUSSION...
A stable trade wind weather pattern remains in place this afternoon,
with latest soundings showing a robust subsidence inversion based
near 6 kft. Satellite, radar and empirical observations indicate
that the trade flow immediately upstream of the islands contains
little in the way of showers, with an area of increased showery low
clouds located about 200-400 miles ENE of the islands. Water vapor
imagery shows a well-developed, nearly stationary low aloft centered
about 650 miles ENE of the islands.

The forecast anticipates that the trade-wind-supporting ridge N of
the islands will weaken slightly over the weekend, then strengthen
early next week, with trade winds speeds following suit. In the
shorter term, the nearby area of increased showers is expected to
arrive early Friday, likely fueling a wet period windward through
the morning.

The low aloft will move toward the islands beginning Friday, passing
N of Kauai Saturday and Sunday. The nearby passage of the low may
act to weaken the low-level subsidence inversion, bringing the
potential for increased cloud and shower coverage over the weekend,
mainly windward. As the low departs to the N early next week, a
strong ridge aloft will support increasing stability as trade winds
increase and become breezy.

&&

.AVIATION...
Breezy trades will continue across the island chain through tonight.
SHRA and low cigs could bring brief periods of MVFR conds over
windward and mauka locations. Otherwise, VFR conds should prevail.

No AIRMETs are in effect at this time. However, an upper-level low
is forecasted to approach the islands this weekend. This could
increase SHRA coverage. As such AIRMET Sierra may be needed
periodically through the weekend.

&&

.MARINE...
High pressure will dominate the central North Pacific through the
weekend and will strengthen even further early next week. Trade
winds will ease over the 24 to 48 hours, but will likely increase to
fresh to strong levels in the coming week. The Small Craft Advisory
(SCA) for the typically windy waters has been cancelled, but
conditions are expected to redevelop Sunday night or Monday morning.

A series of south swells will keep south shore surf near the
summertime average through the weekend. Surf will drop below normal
levels for much of next week.

The current small northwest swell will keep north shore surf
slightly elevated through tomorrow afternoon, then fade out over the
weekend. Typical mostly flat summertime conditions will prevail
along north facing shores next week.

East shore surf will remain well below normal through the weekend,
then trend closer to seasonal levels next week as the trades
strengthen over and upstream of the islands.

&&

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

&&

$$

DISCUSSION...Birchard
AVIATION...Walsh
MARINE...TS/ASB