Nanmadol is expected to grow stronger on Saturday before moving closer to Korea.
According to the state weather agency, this year’s 14th typhoon was passing waters 520 kilometers east of Okinawa at 9 a.m with a central atmospheric pressure of 920 hectopascals and a maximum wind speed of 53 meters per second.
The Korea Meteorological Administration forecast it will develop into a “super strong” typhoon later in the day.
There four categories: medium, strong, very strong, and super strong when the speed exceeds 54 meters per second.
The KMA expects Nanmadol to land in Kyushu on Sunday and come closest to South Korea the following day, between early morning and afternoon.
A typhoon alert may be issued on Jeju and the southeastern coast between Sunday afternoon and Monday morning.
Heavy downpours are forecast in these areas during that period with precipitation of up to 150 millimeters.