548
FXZS60 NSTU 040045
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
145 PM SST Sat Oct 3 2026

.Short term [tonight through Monday night]...
An expansive ridge of high pressure to the south of American
Samoa continues to hold breezy east-southeasterly trade winds
across the territory. Despite mostly clear and dry conditions
throughout the day, increased low-level convective cumulus can be
seen moving into the area from the southeast embedded within the
trade wind flow. These convective clouds may bring a slight
increase in rain chances going into the evening and overnight
hours. However, any showers that do occur should remain light,
brief, and shallow in depth due to a stable trade wind inversion
above the shallow near-surface moist layer as observed in this
afternoon`s 00Z RAOB upper-air sounding.

The ridge of high pressure is holding an active trough to the
north of American Samoa. However, models indicate that slight
weakening of the ridge is likely to allow the trough to drift
closer to the territory by late Monday. While the active core of
the trough is expected to remain just north of the area, GFS
model proximity soundings for American Samoa project the trough
coming close enough to erode the trade wind inversion and
significantly increase atmospheric moisture over the area.
Therefore, expect increased rainfall chances for the end of the
short term forecast period. Widespread flash flooding looks
unlikely at this time, but localized brief periods of heavy
rainfall are possible for this time frame.

.Long term [Tuesday through Saturday]...
Rain chances remain elevated to start the long term forecast
period. However, a high pressure center developing near Australia
and New Zealand should again strengthen the ridge and quickly
push the trough northward and out of the area by midweek. Expect
the trade wind weather pattern to be maintained for the long term
forecast period due to the persistent ridge, with brief passing
showers embedded in the breezy trade wind flow being possible.

&&

.Marine...
The persistent trade wind pattern will continue to hold rough seas
throughout the new week. Wave and surf heights may subside
slightly to start the new week due to a subtle weakening of the
trade winds. However, as the ridge again intensifies by midweek,
expect wave heights to once again build near 10 feet. Given the
anticipated rough ocean conditions, we anticipate the High Surf
and Small Craft Advisories remaining in effect throughout the new
week. Mariners and beachgoers alike should follow necessary
precautions.

&&

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

&&

$$

Barton