Japanese weather officials are forecasting localized torrential rains across the country's west late Monday and in the east on Tuesday. They say warm, damp air and a rain front are causing the unstable atmospheric conditions.
The system brought heavy rains that saturated the ground in parts of the southwestern prefecture of Miyazaki by Monday morning.
The rain front will move across Japan from west to east. Areas along the Pacific coast will see most of the heavy rains.
Hourly rainfall of at least 50 millimeters is expected in western Japan, the central coastal region of Tokai, as well as in Tokyo and its surrounding prefectures.
The Tokai region is expected to get as much as 250 millimeters in the 24 hours leading up to Tuesday evening.
The Pacific coast in eastern and northern Japan will experience gusty winds and rough seas, with waves as high as six meters.
Japan's Meteorological Agency is warning of landslides, swelling rivers, flooding in low-lying areas, high surf, lightning strikes and tornados.