The Greater Tokyo Area will experience several days of moderate to heavy rainfall, from Thursday through Sunday.
A slow-moving storm system has already brought 50-150 mm (2-6 inches) of rain to southern Japan, including the far northern Ryukyu Islands, eastern Kyushu and southern Shikoku. Local rainfall amounts have exceeded 380 mm (15 inches) across southern Shikoku.
The heaviest rainfall will shift into southeast Honshu on Thursday, then advance into Tokyo Thursday night and Friday.
Although the heaviest rain is expected Thursday night and Friday, periods of steady to at times heavy rain will continue across the Greater Tokyo Area through Sunday.
Rainfall amounts will average 25-75 mm (1-3 inches) through Friday. An additional 25-75 mm (1-3 inches) will then be possible from Friday night through the weekend.
Flooding will be a major concern across the region, especially in any poor drainage and urban areas. During the heaviest rainfall, street flooding will be possible in urban areas, while mudslides will be a threat near any areas of higher terrain.
The threat for some rain and even a thunderstorm will continue early next week, but the heaviest rainfall will have ended across the region.