Typhoon Bualoi is crossing over the Northern Marianas, and was about 100km northeast of the main island Saipan on Tuesday morning.
At its centre, the typhoon has winds as high as 200km/h, and the storm was forecast to intensify as it moved into open ocean.
There are currently no reports of major damage in the Northern Marianas.
Schools and government offices are closed again today, and US president Donald Trump last night approved an emergency declaration for the territory.