464 
FXZS60 NSTU 060021
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago  AS
121 PM SST Fri Feb 5 2021

.Short term...

The South Pacific Convergence Zone (SPCZ) is now directly over 
American Samoa. Heavy rainfall occurred throughout Tutuila and 
Aunu'u at times this morning while satellite showed lighter 
showers over the Manu'a region. A rain gauge on the east side of 
Tutuila recorded almost 4 inches of rain this morning. 

The latest balloon data shows a very moist atmosphere, which
matches what the satellite imagery over the territory. Model data
has the core of the rain manuvering to the west of the region at 
times, but precipitable water rates remain at 2.5 inches through 
early Sunday. The upper level low pressure system to the east of 
the region is helping to bring additional moisture to the region 
and the steer the SPCZ over American Samoa. The very moist air at
all levels of the atmosphere along with the convergence of 
airmasses gives American Samoa the opportunity of heavy and/or 
consistent rainfall. Therefore, a Flash Flood Watch is in effect 
through Sunday.

Northeasterly winds will gradually increase from tomorrow night
through Monday as there is pending tropical development near the
Fiji region during this time. Confidence is high that there will
be no tropical development within the American Samoa region for
the next 7 days. However, this will help enhance the trough and
the interaction between the strengthening high pressure to the
east with the trough as well. At this time, winds appear to be
below the Wind Advisory threshold, but will continue to monitor
the winds through out the next few days.

.Long term...

The aforementioned pending tropical system will continue to move
southward from the Fiji region, further away from American Samoa.
However, the SPCZ will still linger between Fiji and American
Samoa during this time. The threat for tropical development will
remain low, but above average rainfall is likely during this time. 

&&

.Marine...

The current data from the PacIOOS buoy to the east of Aunu'u shows
seas around 7 feet throughout the morning hours. The trough is
forecast to bring frequent showers throughout the entire region. Seas
are expecting to build by tomorrow evening as the moderate 
northeasterly breeze is expected to become fresh. The fresh breeze
from Saturday night through Monday will be in the Small Craft 
Advisory criteria for both seas and winds during this time. As the
seas build, high surf is expected for the shorelines of American
Samoa.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...

A Flash Flood Watch is in effect.

&&

$$

LaPlante