American Samoa's Tropical Cyclone Outlook 2025-26

Below Normal to Near Normal Tropical Cyclone (TC) Activity anticipated for American Samoa in the 2025-26 TC Season Read More >

138
FXZS60 NSTU 010045
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
145 PM SST Wed Dec 31 2025

.Short term [tonight through Friday night]...
A dry mid-level airmass, observed in this afternoon`s RAOB upper-air
sounding, should hold stable weather over the territory through
Friday night. This will limit showers at isolated to scattered
throughout the short term period. Any showers that do occur will
be in the passing form. Winds should remain light at under 15
mph, turning out of the north to northeast by Friday.

.Long term [Saturday through Wednesday]...
A pattern shift is expected this weekend as a low to mid-level
shortwave trough is forecast to develop over the territory. This
mid-level trough should increase rain chances throughout the
weekend.

The trough is forecast to peak in intensity on Sunday, bringing
potential for heavy rainfall and possible thunderstorms in the
area. While there is high confidence in timing, there is still
considerable uncertainty regarding intensity of the trough when it
peaks over the area on Sunday. The operational GFS is the
strongest depiction of the trough out of our model suite. The last
several runs of the GFS depict strong low-level winds working
their way down to the surface on Sunday. This GFS solution would
bring breezy conditions that near Wind Advisory threshold on
Sunday, especially for the Pago Pago Harbor region due to
northerly flow interaction with terrain. Other model and
ensemble data still bring increased northeasterly flow, but keep
wind speeds well below advisory threshold.

The trough is anticipated to weaken over the area by the new
week. Easterly winds should take over, driven by high pressure
building to the southeast. Any showers embedded within the
easterly flow are expected to come in the passing form.

&&

.Marine...
Seas have been observed at around 6 feet throughout the day at
Aunu`u Buoy. Light to moderate winds should hold similar ocean
conditions through Saturday. The aforementioned trough is
expected to bring a fresh breeze by Saturday night, which may
further increase to a strong breeze on Sunday depending on the
strength of the trough. Regardless, seas are likely to build to
Advisory levels over this period.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...
None

&&

$$

Barton