Area Forecast Discussion
Issued by NWS Pago Pago

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FXZS60 NSTU 220115

Area Forecast Discussion
National Weather Service Pago Pago  AS
215 PM SST Sun Jan 21 2018

.Short term...
.TONIGHT THROUGH TUESDAY NIGHT...A surface to mid-level trough
will move SW slowly across the Samoan Islands through Tuesday
morning. Ahead of this trough lies a broad surface ridge which
will either weaken or force the trough SW and away from the region
as early as Monday. GFS models highly suggest a wet forecast
period but SWFDDP guidance disagree. Hence, the previous forecast
package suits the expected weather conditions during the next
couple of days. Thus, anticipate numerous showers and isolated
thunderstorms to diminish late Monday night into Tuesday.

.Long term...
.WEDNESDAY THROUGH SUNDAY...GFS computer models now materializes a
surface trough to the ESE of Manu`a on Thursday and Friday before
the arrival of an upper-level trough over the Samoan Islands on
Saturday. Perhaps this emerging trough will produce increasing
rainfall and possible thunderstorms...but for now will keep the
precipitation coverage at scattered showers. Moderate easterlies
will trigger scattered mid-morning to afternoon showers.


.Marine...FNMOC Wave Watch III shows a large NW swell arriving as
early as Wednesday night through Friday. Currently, model guidance
hints at keeping seas and surf heights below advisory levels, but
will keep an eye on this situation and provide updates as future
model runs become available. Thus, anticipate moderate seas to
persist over the next several days.


.A Small Craft Advisory.



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