354
FXZS60 NSTU 240100
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
200 PM SST Mon Jun 23 2025

.DISCUSSION...
The latest satellite imageries continue to show an active trough
south and west of the territory, and an active area just north of
Swains Island. Also shown on satellite imageries are open-cell
cumuli clouds streaming across the territory throughout the day.
These clouds are associated with a strong high pressure system to
the west-southwest migrating east. The open-cell cumuli clouds
have continued to bring passing showers across the territory from
time to time. This feature is further supported by the upper air
observations (RAOB) from this afternoon (24/00Z). Also shown on
the RAOB are backing moderate to strong easterlies up to mid-
levels. Although these observations hints at instability over the
area, the drier mid-levels will likely suppress any vertical
cloud growth, minimizing the potential for numerous to widespread
showers for the next 6 to 12 hours. Model data shows these
conditions with passing showers and moderate to fresh easterlies
remaining for tonight through at least Tuesday morning.

However, model data shows a mid-level low pressure system extending
to the surface level, just north of Swains Island. Model solutions
also show the aforementioned trough to the south and west moving
closer and over the territory by midweek. With the two synoptic
features (mid-level low pressure system and the trough) over the
area, unstable weather conditions will likely increase for this
time frame and remain for the rest of the week. Thus, the
potential for flash flooding conditions with embedded thunderstorms
and gusty winds is expected for Tuesday afternoon through the
rest of the week.

By Sunday, a mid-level high pressure system will build over the
area, bringing adverse weather conditions. Will continue to
monitor as more data becomes available.

&&

.Marine...
Observations of wave heights from the PacIOOS buoy near Aunu`u
show 7 to 9 feet seas with peak periods less than 10 seconds.
However, data from the King-Poloa buoy (PacIOOS) show heights
around 4 to 6 feet with slightly longer peak periods. This data
suggests the much higher wind-driven waves to the east as
easterlies remain around moderate to fresh breeze (15 to 20 knots)
with higher gusts at times. Hence, the small craft advisory
remains in effect and may likely continue for the rest of the
week.

Furthermore, model data shows an upward trend in seas as a trough
to the south moves closer and over the area by Tuesday afternoon
through the end of the week. Although model data show winds
decreasing to a gentle to moderate flow by Tuesday night, seas
are expected to peak on Wednesday night through the end of the
forecast period as the aforementioned trough moves over the area.
Peak periods from this southerly swell will likely be more than
10 seconds long, increasing the potential for higher surfs and
strong rip currents.

&&

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

&&

$$

JTAllen