980
FXZS60 NSTU 060118
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago  AS
218 PM SST Tue Aug 5 2025

.DISCUSSION...
The latest satellite imageries shows the trough to the north and
east moving closer to the islands. Additionally, another trough to
the south and west of the islands looks to be moving closer to the
area. The position of these two synoptic features will likely
determine local weather patterns for the upcoming days. On
satellite imageries, sky conditions show partly cloudy with
minimal moisture over the area. These conditions are reflected on
the latest upper air observations (ROAB) from this afternoon
(06/00Z)-a deep inversion from the 850 mb (~5000 ft) level to 550
mb (~16000 ft). These conditions is likely reflecting current
conditions and the next couple of hours. However, both the ECMWF
and GFS model data projects the earliest arrival of the trough
over the islands tonight, increasing throughout the overnight
hours tonight through Wednesday and decreasing by Wednesday night.
Based on the latest satellite imageries and model data, the
probability for increased showers and thunderstorms is much
higher. Will continue to monitor conditions as more data becomes
available. In the meantime, a flood watch is now in effect for
tonight through at least Wednesday night.

Gentle to moderate (10 to 15 mph) east winds will remain for
tonight through early Wednesday, turning northeast on Wednesday
afternoon and decreasing to light and variable (<10 mph) on
Thursday through Thursday night. Winds will slightly increase to a
gentle (10 mph) southeast breeze on Friday through Friday night.
A moderate trade wind flow is expected Saturday through Sunday
night increasing to a fresh (20 mph) breeze on Monday through the
end of the forecast period.

Long term model projections show the trough moving back northward
by Thursday and Thursday night as it weakens. This is due largely
to a high pressure system to the southwest migrating east and
pushing the trough back north. Expect numerous showers for tonight
becoming widespread showers for the short term forecast period.
A decrease in showers to scattered is expected for the long term
period.

&&

.Marine...
Manual observations of seas and surfs reaching the roads and
collecting debris in the coastal areas were high enough to prompt
a high surf warning earlier in the day. This was further
supported by observations recorded by the PacIOOS buoy near
Aunu`u. Sea heights of 10 to 13 feet with periods around 12 to 14
seconds, enhancing surfs to 13 to 16 feet was recorded at the
Aunu`u buoy. These data sets together with the manual observations
prompted the issuance of a high surf warning for the east to
south to west facing shores of all islands through tonight.
Previous model runs did not get a good handle on this event,
underestimating heights and periods. However, the latest model
data shows a downward trend starting tonight. Once this large
south swell passes the area, no other significant swell is
expected for the rest of the forecast period (up to 5 days). Winds
are expected to remain at a gentle to moderate east breeze before
turning southeast by the end of the week. Thus, a high surf
warning remains in effect through tonight and will likely be
downgraded to a high surf advisory thereafter. A small craft
advisory also remains in effect.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...
High Surf Warning for east-south-west shores
High Surf Advisory for north shores
Small Craft Advisory
Flood Watch

&&

$$

JTAllen