National Weather Service Raw Text Product

519 
FXZS60 NSTU 210259
AFDPPG

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

.Discussion...
Current satellite images show that the center of Tropical Cyclone 
Vicky is about 75-100 miles south of Tutuila, and is moving 
generally southeastward away from the area. Surface pressures 
over the islands are rising, and winds are on the downtrend. 
However, model guidance indicates another surge in moisture late 
tonight into Friday, as another developing low approaches from the 
west. This developing area of low pressure near Wallis and Fatuna 
(about 450 miles west-northwest of Tutuila) is moving east-southeast 
at 10 to 15 mph, and is the subject of a tropical cyclone formation 
alert from the Joint Typhoon Warning Center. Tropical cyclogenesis 
appears increasingly likely over the next 24 hours as the low moves 
very close to the islands, and a Tropical Storm Watch has been 
issued for all areas except Swains. 

Model guidance indicates that this low could pass dangerously 
close to the islands late Friday into Saturday, potentially bringing 
another round of high wind, flooding rain and high surf. 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. There looks to be time on Friday to make preparations, 
but heavy rainfall and locally gusty winds in advance of the system 
could hamper those efforts.

The 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 
have diminished, seas are responding by gradually diminishing, and 
the Gale Warning has been cancelled. Mariners are encouraged to 
remain in port however, as a developing low to the west-northwest is 
expected to move close to the islands Friday night and Saturday. 
Difficult to pinpoint exact details of the impacts this low will 
bring, but strong winds, rough seas and visibility near zero in 
blinding rain are distinct possibilities, and a Tropical Storm Watch 
has been issued. Even before the low arrives, an increase in 
gusty showers is expected to arrive from the northwest late tonight 
and Friday. 

After this low moves away from the area late Saturday and Sunday, 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...
Tropical Storm Watch
Flash Flood Watch 
High Surf Warning

&&

$$

Birchard/HFO