Torrential rains are expected to lash the northern and northeastern regions of Japan again on Tuesday.

The Meteorological Agency says unstable atmospheric conditions in northern Japan are due to an influx of warm, moist air toward a front hanging over the Sea of Japan.

Rain clouds are developing over the northern Tohoku region and Hokkaido.

The risk of mudslides surged in Aomori Prefecture due to the large amount of rain the region has received so far. Landslide warnings are in place for some areas of the prefecture.

A low-pressure system accompanied by a front is on course to pass over northern Japan on Tuesday and move down toward western Japan the following day.

On Tuesday, heavy rain is forecast in Tohoku's coastal areas along the Sea of Japan, with more than 80 millimeters per hour of rain expected in some places.

In the 24 hours through Tuesday evening, up to 250 millimeters of rain are expected in the Sea of Japan coastal areas in Tohoku; 150 millimeters in coastal areas along the Pacific Ocean in Hokkaido and Tohoku; and 80 millimeters in Niigata Prefecture.

In the following 24-hour period through Wednesday evening, between 100 and 200 millimeters are expected in Niigata Prefecture, the Hokuriku region and the Chugoku region; between 100 and 150 millimeters in the northern Kyushu region; and between 50 and 100 in Tohoku.

Meteorological Agency officials are warning of landslides, swollen rivers and flooding in low-lying areas.

Meanwhile, eastern and western Japan can expect sweltering conditions on Tuesday.

The city of Maebashi in Gunma Prefecture and the city of Kumagaya in Saitama Prefecture will see a daytime high of 39 degrees Celsius, while a high of 38 degrees is expected in the cities of Utsunomiya and Saitama.

Daytime highs will be 37 degrees in the cities of Oita, Takamatsu and Toyama; 36 in central Tokyo and the cities of Matsuyama and Miyazaki; and 35 in the cities of Fukuoka, Osaka and Fukushima.