Japanese weather officials warn that warm and moist air may bring strong thunderstorms to some parts of the Kanto and Tohoku regions through Tuesday.
The Japanese Meteorological Agency said the air is flowing into the regions along the edge of a high pressure system and a tropical depression, which has weakened from Tropical Storm Kirogi.
Weather officials say the warm and moist air is causing rain to fall mainly in areas along the Pacific in eastern and northern Japan. They added that rain clouds are developing in certain areas of the Kanto and southern Tohoku regions.
As much as 100 millimeters of rain is expected in 24 hours through Tuesday morning in some areas of the Kanto region, the Izu Islands and along the Pacific in the Tohoku region.
The officials say Hokkaido may also experience sudden thunderstorms and gusts.
They are warning of potential mudslides, flooding in low-lying areas, lightning strikes, tornadoes and other strong gusts and even hail.