Area Forecast Discussion
Issued by NWS Pago Pago

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FXZS60 NSTU 240041

Area Forecast Discussion
National Weather Service Pago Pago  AS
141 PM SST Mon Oct 23 2017

.Short term...
TONIGHT THROUGH WEDNESDAY NIGHT...Latest satellite imagery shows a
blob of showers with embedded thunderstorms streaming across the
Samoan islands this afternoon. This is associated with a surface
trough just to the North of the islands, that is slowly drifting
Westward. Current model data show these showers on a downward
trend tonight as the trough moves further west. A surface ridge to
the south of the Samoan islands will continue to support gentle to
moderate trades across the forecast area through the short term.
With the passing of the showers tonight, the surface ridge will
dominate weather conditions Tuesday through midweek.

.Long term...
THURSDAY THROUGH MONDAY...Current model data show the
aforementioned ridge weakening Thursday as the associated high
pressure system move further east. This will allow for another
trough from the north to move across the Samoan islands by
Thursday night. If this scenario plays out, we expect an uptick in
showers and clouds and gusty winds Thursday night through the
weekend. However, since model data skills are low beyond day 3,
will keep previous forecast and make necessary adjustments when
confidence in model output is high.


Latest PacIOOS Aunu`u wave buoy show heights lingering near
advisory criteria this afternoon. These heights far exceed
forecast values. Hence, will extend advisories for high surfs and
small crafts through tonight and consider cancellation by Tuesday
if observations agree with forecast values, which are anticipated
to remain below advisory criteria.


High Surf Advisory extended until Tuesday afternoon.
Small Craft Advisory extended until Tuesday afternoon.



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