Typhoon Chanthu is approaching the Yaeyama region of Okinawa Prefecture, southwestern Japan.
Japan's Meteorological Agency says the typhoon was moving north at about 20 kilometers per hour as of 7:00 a.m. on Sunday, Japan time.
It has a central atmospheric pressure of 935 hectopascals, and central winds of 180 kilometers per hour, with gusts up to 252 kilometers per hour.
The typhoon is likely to continue moving north and approach the Sakishima Island chain in Okinawa Prefecture on Sunday afternoon to evening while retaining its power.
The agency is advising people in the region to be on high alert for violent winds.
Vigorous winds of up to 162 kilometers per hour are forecast for the Yaeyama region, including the islands of Yonaguni and Ishigaki, shortly after midday on Sunday. Maximum gusts of 234 kilometers per hour are expected.
The agency is advising people in the region to evacuate to strong buildings before stormy winds begin to blow, and stay indoors away from windows.
It says in past typhoons of this level, winds knocked down utility poles and concrete block walls, and turned vehicles on their sides.
Rough seas are already visible in the Yaeyama region and waves will likely be as high as ten meters shortly before midday.
Clouds from the typhoon are beginning to shroud the area, bringing intermittent but heavy rain.
As more developed clouds cover the region, extreme rain with thunder is expected.
Over the 24 hours until Monday morning, 180 millimeters of rain will fall in the Yaeyama region.
Caution is also advised for possible lightning strikes and gusty winds.