Area Forecast Discussion
Issued by NWS Pago Pago

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FXZS60 NSTU 260051

Area Forecast Discussion
National Weather Service Pago Pago  AS
151 PM SST Fri Sep 25 2020

Current satellite visible imagery shows a line of convective
cumulus clouds moving over the Samoa Island chain. This feature is
associated with a weak surface trough expected to remain over the
territory through early tonight. Although upper air sounding
00Z/26 depicts a dry and stable profile, the surface remains
fairly moist. However, model solutions show moisture diminishing
overnight as a high pressure system southwest moves in the area.
This feature is anticipated to drive weather through midweek next
week. Hence, expect breezy conditions and showers embedded within
the easterly trade wind flow.

For the long term forecast, model solutions show an uptick in
showers by Wednesday as a low develops near Tonga. Following
behind the low is another high pressure system forecast to bring
another round of winds through the rest of the forecast period.

Latest observations from the Aunu`u PacIOOS buoy shows observed
wave heights slightly exceeding forecasted values and averaging
near 7 feet. Although wave heights remain below advisory
thresholds, sporadic peak periods greater than 13 seconds have
been reported. This is due to a southerly swell anticipated to
brush near the territory tonight and through the weekend.
Furthermore, latest ASCAT passes indicate winds 20 to 25 kts
edging south of the Islands. Wave Watch III model data depicts a
building trend in seas directly related to breezy conditions
expected tonight and through the new week.





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