Tropical storm warnings have been issued for the Northern Marianas and Guam as Tropical Storm Goni approaches the island chain.
Evacuation centres have been opened in both territories and residents have been urged to secure their properties and stock up on supplies.
Extensive flooding has been reported in Guam, after four inches of rain fell on the island today.
Goni is currently about 185 kilometres east, northeast of Guam and about 120 kilometres south, southeast of Saipan, which is still reeling from a direct hit by category three typhoon Soudelor two weeks ago.
A senior meteorologist with the US National Weather Service on Guam, Paul Stanko, says the storm isn't likely to develop into a typhoon by the time it reaches the Marianas.
However, Mr Stanko says Goni is intensifying, albeit slowly, and people should be prepared by the time it passes between the islands of Tinian and Rota tomorrow morning.