Weather officials say heavy rains are expected mainly in northern Japan through Tuesday. They are calling on residents, especially in Yamagata and Akita prefectures, to be on alert for possible landslides and other disasters.
The Meteorological Agency says warm and damp air is flowing toward a seasonal rain front around northern Japan and a low-pressure system on the front, bringing rain to the region.
The agency officials say the seasonal rain front is expected to move south to around the Hokuriku region by Tuesday.
Officials say the unstable atmospheric condition would continue in northern Japan, such as Yamagata and Akita prefectures that experienced downpours last week.
They also say it is feared that localized torrential rains will fall in the region.
The Hokuriku region and Niigata Prefecture, along the Sea of Japan coast, are also expected to see heavy rains on Tuesday.
In the 24 hours through Tuesday evening, up to 120 millimeters of rain is forecast in Hokuriku and Niigata, 80 millimeters in the western side of the Tohoku region, and 60 millimeters in the Pacific side of Tohoku and Hokkaido.
Residents in Yamagata and Akita are advised to exercise caution against landslides and flooding, as well as lightning and gusty winds. That is because the ground has been loosened and river levees have been damaged in some locations. The risk of disaster could rise again even with a small amount of rain.