Tropical Storm Yun-yeung is traveling north-northeast over the sea south of Japan. It may approach eastern and northern Japan through Saturday.
Japan's Meteorological Agency says Yun-yeung is traveling at 25 kilometers per hour. Extremely heavy rain accompanied by thunder is expected in eastern Japan through Saturday.
Weather officials are warning that bands of heavy rain clouds may develop over the Izu Islands through Friday morning, which could sharply heighten the risk of disasters.
In the 24 hours through Friday morning, as much as 250 millimeters of rain is expected in the Izu Islands, 150 millimeters in the Tokai region and 100 millimeters in Kanto-Koshin.
In the 24 hours through Saturday morning, 100 to 200 millimeters of rain may fall in the Kanto-Koshin and Tokai regions, and 100 to 150 millimeters in the Izu Islands. Some areas may get more rainfall if bands of heavy rain clouds form.
Weather officials are warning of mudslides, floods in low-lying areas and swollen rivers. They are also urging caution against lightning strikes, tornadoes and strong gusts.