The Meteorological Agency says the storm was at sea 280 kilometers south-southeast of Choshi in Chiba Prefecture, neighboring Tokyo, as of 11 a.m. Thursday, Japan time. It says the storm was almost stationary.
The storm was packing maximum winds of over 80 kilometers per hour near its center.
The Pacific coast of Tohoku can expect heavy rain.
Up to 100 millimeters of rain may fall in some parts of Tohoku and 80 millimeters in Kanto during the 24 hours ending Friday morning.
Wind is expected to intensify in these areas through Friday. Maximum winds of over 80 kilometers an hour are expected along the Pacific in Kanto and Hokkaido, and over 70 kilometers on the Izu Islands and in Tohoku.
Seas will be rough, with high waves of 7 meters likely to occur off the coasts of Kanto and Tohoku until Friday.