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 >

192
FXZS60 NSTU 210048
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
148 PM SST Mon Apr 20 2026

.DISCUSSION...
Mostly cloudy skies with numerous showers, heavy at times with
light winds have been observed throughout the day. Also observed
is an active area of thunderstorms just south, gradually
deepening and moving closer to the islands. These unstable
conditions are also shown on the upper air observations (RAOB)
from this afternoon (21/00Z) with elevated convective energy,
increased precipitable water content, and signals of thunderstorm
activity. This instability will continue to linger over the area
as a shortwave trough moves across the territory, tonight. Shown
on the latest model solutions is a high pressure system anchored
southeast, generating gentle to moderate easterlies pushing the
trough further west and south of the islands by Tuesday. Once
the trough passes, the aforementioned high pressure system will
keep the moderate easterlies with embedded showers through at
least Friday.

By late Friday, model data is showing another high pressure system
to the southwest migrating east as it maintains moderate southeast
winds for the rest of the forecast period. These southeasterly
winds signals at an early trade-wind season. However, will
continue to monitor conditions as more data becomes available.

Thus, expect numerous showers, heavy at times with possible
thunderstorms and light east winds for tonight. Much improved
conditions with scattered showers and gentle to moderate east-
southeast winds is expected for the rest of the forecast period.

&&

.Marine...
Calm and smooth seas continue to remain over the area. These
conditions are further supported by data reported from the PacIOOS
buoys (Aunu`u & King-Poloa) with heights lingering in the 3 to 5
feet range. Model data show these heights remaining over the area
through at least Tuesday. However, model data also show a
southwest swell moving into the area by Tuesday night and remain
through Wednesday. This swell coupled with moderate east-southeast
winds will produce rough conditions in the coastal waters. Also,
with swell periods projected to peak at more than 15 seconds long,
expect higher surfs and strong rip currents to impact the west to
south facing shores of all islands. By Wednesday night, a
downward trend in seas will produce favorable conditions for the
rest of the forecast period. There are no other significant swells
expected for this period.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

JTAllen