327
FXZS60 NSTU 010111 CCA
AFDPPG

Area Forecast Discussion...CORRECTED
National Weather Service Pago Pago  AS
211 PM SST Sun May 31 2026

.Short term [tonight through Tuesday night]...
Strong surface high pressure is expected to continue to increase
the strength of the southeasterly trade winds 20 to 30 mph with
higher gusts tonight through Tuesday. Embedded in this strong
trade wind flow is a subtle surface trough bringing increased
shower activity to the islands. The moist and unstable low-levels
of the atmosphere observed in this afternoon`s 00Z RAOB upper-
air observation favor this enhanced shower activity. However,
significant dry air in the mid and upper-levels of the atmosphere
(around 4 km agl and above) was also observed in this sounding.
This dry air aloft makes thunderstorm chances very low and should
keep showers disorganized in more of a passing form. The heaviest
showers may produce localized ponding on roadways and minor
flooding, but widespread flash flooding is not expected at this
time. By Tuesday into Tuesday night, the trough should slowly
move north and out of the area. The southeasterly trade winds
are forecast to slightly weaken by Tuesday night, but will still
remain breezy at 15 to 25 mph.

.Long term [Wednesday through Sunday]...
By Wednesday, a strong upper-level ridge pattern is forecast to
take over across the region, persisting through the weekend.
There is strong consensus amongst model and ensemble solutions
that this will lead to well below average atmospheric moisture
levels, with the mid-levels of the atmosphere being substantially
dry. GFS proximity soundings over American Samoa throughout the
long term forecast period depict that the mid-levels of the
atmosphere will be completely stable. Rain chances are forecast
to be low through the long term forecast period, and any rainfall
that does occur will be brief and shallow, below the mid-level
stable layer. Therefore, there is high confidence that rainfall
will be below average and deep convection will not occur over
American Samoa throughout the long term forecast period.
Continued surface ridging to the south is expected to maintain
breezy east-southeast trade winds through the long term forecast
period.

&&

.Marine...
Seas of 9 to 11 feet characterized by a combined sea state with
long period southerly swell and southeasterly wind waves has been
observed today at Aunu`u and Poloa buoys. The long period swell
is forecast to diminish with time tonight as wind speeds continue
to increase 20 to 25 knots with higher gusts. This will lead to a
transition to a sea state that is dominated by southeasterly wind
driven waves by tomorrow. The increase in wind speeds may
slightly further build seas 10 to 13 feet Monday and Tuesday.
This will lead to continued hazardous marine and surf conditions.
Mariners and water recreationists alike should proceed with
extreme caution. The forecast through Tuesday presents marine
conditions capable of making navigation dangerous and difficult
to impossible for small crafts, with surf heights that can easily
sweep away people that get too close to the water. The potential
for rip currents will also be strongly elevated, even if
conditions initially appear safe.

By midweek, winds are expected to slightly decrease from a strong
breeze into a fresh breeze. This should allow wave heights to
slightly subside starting Tuesday night. Despite the slight
reduction in wave heights, Small Craft Advisory criteria is still
expected to be met throughout the latter half of the new week.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...
High Surf Warning
Small Craft Advisory

&&

$$

Barton