Severe tropical storm Krosa will likely approach western Japan on Wednesday, weather officials say. It is currently south of the country over the Pacific and moving northwest toward the country.
The meteorological agency warns that heavy rain is expected in western and eastern Japan on Tuesday afternoon as a mass of moist air hits these areas ahead of Krosa's arrival.
The agency says the zone of strong winds has expanded to more than 1,600 kilometers across, large enough to cover the entire island of Honshu.
Krosa is expected to be whipped up by warm sea temperatures and make landfall in western Japan through Thursday.
There are already high waves near the Ogasawara islands south of Tokyo. Okinawa and other southwestern islands are also being hit by big waves, as are western and eastern Japan.
Weather officials warn that up to 200 millimeters of rain is expected over a 24-hour period through Wednesday evening in the Tokai and other regions. Another 200 to 300 millimeters is expected over 24 hours through Thursday evening over wide areas. Additional precipitation is expected beyond that.
The stormy weather and threat of landslide could disrupt the traditional Bon holiday period.