Area Forecast Discussion
Issued by NWS Pago Pago

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FXZS60 NSTU 210025

Area Forecast Discussion
National Weather Service Pago Pago  AS
125 PM SST Fri Oct 20 2017

.Short term...
TONIGHT THROUGH SUNDAY NIGHT...Latest satellite imagery shows the
active surface trough that has been bringing recent showers
across the territory remaining south of the Samoan islands.
Current model data show this trough slowly dissipating through
Saturday as a building high pressure to the southwest migrate
eastward. With the building high, we anticipate moderate to fresh
trades to return across the forecast area by Saturday through the
remainder of the weekend. Showers will also be minimal as the
associated ridge prevails weather conditions across the area.

.Long term...
MONDAY THROUGH FRIDAY...Current model data show a surface trough
developing north of Manu`a islands, bringing an uptick in showers
Monday through Tuesday as this trough is forecast to move
Westward and dissipate. Gentle to moderate easterlies will
dominate as the aforementioned high pressure continue to move
further east.


Current PacIOOS Aunu`u wave buoy observations show a large
Southwesterly swell as the dominant factor for heights this
afternoon. Latest Wave Watch III/SWAN model data show heights
lingering on the threshold between 7 and 9 feet Saturday afternoon.
Winds are also expected to reach fresh levels by Saturday
afternoon. Hence, we anticipate the issuance of at least a small
craft advisory due to winds and analyze further on whether heights
will also meet criteria for a high surf advisory by Saturday





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