Showers are forecast to continue today with the Department of Education cancelling school for a second day.
American Samoa Meteorologist Salu Malala Salu said the approaching depression was expected to intensify within the next 24 hours.
"There's a tropical depression ... and it's located about halfway between us and Fiji. Looking at the models, it should come near Savai'i and Upolu [in Samoa] late tonight," Mr Salu said.
"By the time it reaches Savai'i and Upolu it should be a tropical storm, meaning winds of 30 to 45 miles per hour and then it should come over us [in the] morning as it tracks going southeast."