The Joint Typhoon Warning Center said the storm, named Mawar, has strengthened to typhoon status and the Marianas will see tropical storm conditions, which may last 12 to 18 hours reports RNZ Pacific.
As of 2am local time on Monday, the centre of Tropical Storm Mawar was moving north-northwest at 13k/ph, and is expected to make a slight turn.
As a result of the approaching typhoon, a flood watch, small craft advisory, and high surf advisory are in effect until Thursday.