The Japan Meteorological Agency warned on Saturday of a large and powerful typhoon expected to reach landfall in the southern island of Kyushu on Sunday, bringing up to half a metre of rain.

The agency said it may issue a “special warning” for Kagoshima prefecture and other parts of Kyushu, Japan’s southernmost main island, as early as Saturday evening with the possibility of high waves and heavy rains in the regions.

“Unprecedented” storms and rainfall could strike the area, JMA official Ryuta Kurora said at a televised press conference, urging residents there to evacuate before it gets dark.

Southern Kyushu could receive 500 millimetres of rain on Sunday, while the central Tokai region could see 300 millimetres, the agency forecast.

Typhoon Nanmadol, the 14th of the season, was near Japan’s southern Minami-Daito Island heading northwest at 20 km (12 miles) per hour on Saturday afternoon. The storm is forecast to curve east and pass over Tokyo on Tuesday before moving out to sea by Wednesday.

Domestic broadcasters aired footage of strong winds and rain are already lashing down on Japan’s southern island chain of Okinawa as the storm approached.