A strong typhoon, the 17th of the season, was moving north-northwest in waters west of the Ogasawara Islands and was expected to approach the Izu Island chain by Saturday afternoon, the Meteorological Agency said.
The agency said it was unlikely to make landfall on mainland Japan, but the Kanto region would see clouds and rain over the weekend.
As of 10 p.m. Friday, Typhoon Saola -- the Vietnamese name for a rare forest-dwelling ox -- was located some 500 km south of Hachijojima Island in the Izu chain, the agency said. It was moving north-northwest at a speed of 15 kph.
Packing winds of up to 144 kph, Saola had an atmospheric reading of 950 hectopascals.