690 
FXZS60 NSTU 202356
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago  AS
Issued by National Weather Service Honolulu HI 
156 PM HST Thu Feb 20 2020

.Discussion...
Current satellite images show that the center of newly-formed 
Tropical Cyclone Vicky is just south of Tutuila, and is moving 
generally southeastward away from the islands. Surface pressures 
over the islands are, and weather will gradually improve overnight, 
but areas of heavy showers and thunderstorms will continue to bring 
the potential for locally strong and gusty winds. 

A brief break in the recent extreme weather is expected to be short-
lived as another tropical low has formed within the active monsoon 
trough over the region, and is currently centered near 12S 177W, or 
about 450 miles west-northwest of Tutuila. Latest model guidance, 
(which has not performed exceptionally well with the details of the 
recent weather) indicates that this low could pass dangerously close 
to the islands as it strengthens late Friday into Saturday, 
potentially bringing another round of high wind, flooding rain and 
high surf. Tropical cyclone intensity forecasting is an ongoing area 
of research, and forecasting the future intensity of incipient 
tropical cyclones is a low confidence endeavor. Therefore details 
on the specifics of the potential impacts are difficult to 
accurately pinpoint, but residents and visitors should anticipate 
another round of locally damaging winds and torrential rain with 
this system. 

This low is expected to depart the area by Saturday night, 
leaving the islands in a convergent northerly flow that will 
likely persist into the middle of next week. While this appears to 
keep the threat of heavy showers and thundershowers over the area, 
winds will be much lighter, mainly in the 10 to 20 mph range. 

&&

.Marine...
Gale force winds associated with Tropical Cyclone Vicky 
are gradually diminishing, and seas are responding by gradually 
diminishing, as supported by data from the Aunuu buoy. As the 
cyclone moves away from the area tonight, winds and seas may 
diminish somewhat, but this is expected to be short-lived as yet 
another tropical low is expected to cross the region - potentially 
as early as Friday night/Saturday. Gale force winds and rough 
seas are expected with this system as well. After this low moves 
away, a wet northerly flow is expected to prevail, bringing the 
potential for thunderstorms, but winds and seas should generally 
trend down.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...
Gale Warning
Flash Flood Watch
High Wind Warning 
High Surf Advisory

&&

$$

Birchard/HFO