Western Japan has been experiencing bursts of intense rain and lightning. Bands of clouds that cause such torrential rain could form over Yamaguchi Prefecture and northern parts of the Kyushu region through Monday morning, sharply raising the risk of rain-related disasters.
The Japan Meteorological Agency says warm and damp air has been flowing toward a seasonal rain front over the country, destabilizing atmospheric conditions.
Bands of heavy rain clouds developed over the city of Goto in Nagasaki Prefecture on Sunday morning. Rainfall in an area of Miyazaki Prefecture exceeded 100 millimeters in a one-hour period shortly after noon on the same day.
Downpours accompanied by lightning could sweep across eastern and western Japan through Monday.
Total precipitation in the 24 hours through Monday evening could reach 200 millimeters in northern Kyushu and 120 millimeters in Yamaguchi Prefecture and southern Kyushu.
Meteorological agency officials are warning of mudslides, floods and swollen and overflowing rivers.