174
FXZS60 NSTU 190828
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
928 PM SST Fri Apr 18 2025

.Update...
The complex of showers and thunderstorms over Independent Samoa
mentioned in the previous discussion has since weakended over the
past several hours, leaving calm conditions and remnant upper-level
cirrus clouds over the Samoan Islands. Additional development of
showers has occurred to the north and east of the territory, but
many of these showers have also struggled to maintain themselves.
Still, latest water vapor satellite imagery does show abundant
moisture for additional redevelopment of convection in the area.
However, with no clear area of widespread rainfall threatening
American Samoa at this time, we will downgrade rain chances to
numerous showers and a very small chance of a thunderstorm for the
remainder of tonight in the evening forecast updates.
Additionally, a Small Craft Advisory has been issued for the
remainder of tonight as a swell may elevate seas to near the 8
foot threshold. Otherwise, the extended forecast remains the
same.

&&

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

&&

$$

Barton/LaPlante

&&

.Previous discussion... /issued 215 PM SST Fri Apr 18 2025/

Short term...
Latest satellite data shows thunderstorms over Independent Samoa,
associated with a trough west of the Samoa Island chain. These
showers are expected to move over the territory tonight as a high
pressure system to the south moves east. Expect an uptick in
showers tonight through Saturday morning as it moves across the
Islands. By Saturday afternoon, showers will briefly diminish in
the area before another round of showers further west moves
towards the Islands by night. The potential for flash flooding is
possible for this time through Sunday. We will continue to
monitor later satellite observations to see how the trough
progresses.

Long term...
By Monday, the trough will weaken as high pressure builds over the
region, supporting fair weather through Tuesday. Winds remain
light and variable until Wednesday, then shift south as a ridge
strengthens near New Zealand. Wind speeds may increase to around 15
mph through Friday, with a developing trough on Friday night
likely bringing more widespread showers by the week`s end.

Marine...
Wave heights have gradually subsided to 5 to 7 feet this
afternoon as winds have diminished below 10 knots. As a result,
the Small Craft Advisory is cancelled. Seas are expected to remain
below advisory thresholds for the upcoming week. However, peak
periods are expected to build by Monday as winds build from the
south. Conditions will continue to be monitored.

&&

$$

TM