559
FXZS60 NSTU 020100
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
200 PM SST Sat Aug 1 2026

.Short term [tonight through Monday night]...
Trade winds have weakened today as a ridge of high pressure to
the southeast continues to move out of the area. A surface trough
was observed yesterday to the north of the territory associated
with the boundary between trade winds and weaker equatorial
winds, but with the weakening of the trade winds this trough has
since fizzled out. However, there are still plenty of passing
showers lingering in the area in a disorganized manner apparent
via satellite. This afternoon`s 00Z RAOB upper-air sounding
revealed an environment that is becoming increasingly favored for
these passing showers as the trade wind inversion is now almost
fully eroded and increasing atmospheric moisture is evident.
Conditions will remain similar through the remainder of the short
term forecast period as American Samoa remains in between weather
patterns.

Therefore, expect light winds and scattered to numerous showers
(50-60% chance) through the short term forecast period. Some
showers may produce localized heavy rainfall and minor flooding
of vulnerable roadways and small streams. However, widespread
flash flooding is unlikely as showers remain disorganized.
Temperatures warm to near or slightly above average as
southeastly winds are no longer transporting cool air into the
region.

.Long term [Tuesday through Saturday]...
A ridge to the southwest with surface high pressure center
currently between Australia and New Zealand will be the next
weather maker across the Tropical Southwest Pacific. By midweek,
the high pressure center will move over New Zealand as the ridge
quickly intensifies. Winds will turn back out of the southeast to
start the week and become breezy by midweek. Any subtle
convergences in the strengthening trade wind flow may enhance
shower activity as there is not yet expected to be a trade wind
inversion through the first half of the week (Monday through
Wednesday), minor localized flooding will remain possible with
abundant moisture over the territory. By the second half of the
week into the next weekend, wind speeds will further strengthen
to near-advisory levels. The potential for localized flooding is
expected be decrease over this time frame (Thursday through
Saturday), as the strengthening ridge gradually builds a trade
wind inversion over the territory.

Therefore, expect trade winds out of the southeast to develop over
the long term forecast period. These winds will gradually
strengthen through late week. A Wind Advisory may be needed by
the second half of the week into the weekend. Minor localized
flooding is possible through the first half of the long term
period, but becomes less likely for the second half.

&&

.Marine...
Despite the decrease in wind speeds today, the south swell
continues to linger across the area. Wave heights remain elevated
in the 7 to 9 foot range at Aunu`u buoy, outperforming model
forecasts. Therefore, High Surf and Small Craft Advisories remain
in effect through at least this evening. Model data still
indicates that seas and surf will subside below advisory levels
by the latter half of the weekend into early next week.

By midway through the new week, seas and surf should rapidly
build back to advisory levels as trade winds strengthen to gusty
conditions. By Thursday, as trade winds intensify to a strong
breeze, seas are forecast to build to dangerous heights of over
10 feet, with surf potentially exceeding warning levels. This
will bring dangerous conditions that mariners and beachgoers
alike need to be aware of.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory remains in effect.
Small Craft Advisory remains in effect.

&&

$$

Barton