Area Forecast Discussion
Issued by NWS Pago Pago

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FXZS60 NSTU 170115

Area Forecast Discussion
National Weather Service Pago Pago  AS
215 PM SST Mon Oct 16 2017

.Short term...
.TONIGHT THROUGH WEDNESDAY NIGHT...A surface to mid-level trough
will slide WSW of Savaii and Upolu through Tuesday. As the
jetstream passes south of the region...increasing cloudiness and
locally heavy rainfall are expected especially during mid-morning
to afternoon hours. GFS model solutions materializes a surface to
mid-level ridge upstream which will encourage the southwest
movement of the aforementioned trough to drive SW slowly through
Wednesday. As the surface to mid-level trough lounges comfortably
WSW of the area combined with locally sea-breeze conditions...wet
weather conditions and isolated thunderstorms are expected to keep
the area saturated over the next few days.

.Long term...
.THURSDAY THROUGH MONDAY...An elongated surface to mid-level trough
WSW will bring scattered to numerous showers through Friday. GFS
models continue to show a strong demarcation of this trough axis
which will enhance increasing weather activity around the Samoan
Islands during the next several days. As a surface to mid-level
ridge upstream moves closer to the area...the aforementioned
trough will also push forward to stay close near Savaii and Upolu
during long-term period.


.Marine...A long-period SW swell from well southwest and southeast
near New Zealand will track toward the Samoan waters around Thursday/Friday
while a NE swell will enter the area Friday morning. Will continue
to monitor these separate events before updating long-term sea
heights forecast. For now...anticipate moderate seas over the next
few days.





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