The National Weather Service issued a tropical storm warning for American Samoa as Tropical Cyclone Amos moves toward the U.S. territory.

Earlier this afternoon, the storm was about 310 miles northwest of the main island of Tutuila, moving east at 10 mph. The storm was expected to take a turn to the east-southeast during the next 24 hours.

Sustained winds were at about 100 mph with gusts to 120 mph earlier today.

On its current track, the storm should continue to strengthen and will likely pass southwest and then south of the islands of Tutuila and Manu Saturday night through Sunday.

If the storm takes a more northerly track, it will bring a threat of more widespread damage from winds and rains.

The storm will likely bring flooding, rain and damaging winds as it passes, according to Accuweather.com.

Forecasters expect tropical-storm-force winds and gusts to reach the islands Saturday morning.

Besides the tropical storm warning, all of American Samoa is also under a high surf warning and flash flood watch.

“Heavy rainfall and runoff may cause small streams to overflow, resulting in flooding of low-lying areas and roadways,” forecasters warned.

Surf is expected to build to 16 to 18 feet tonight and 20 to 24 feet on Saturday.

NASA released a photo of the storm, taken today, when sustained winds were at about 104 mph, making it a Category 2 storm.

Forecasters said Amos could reach Category 4 strength of 132 mph, making it a major storm.