Weather officials are urging vigilance over possible landslides and flooding triggered by localized downpours in the Chugoku region of western Japan.
The Meteorological Agency says an active seasonal front has brought record rainfall in Hiroshima Prefecture and elsewhere in the region for half a day.
The officials are also calling on people in wide areas of western and eastern Japan to brace for localized heavy rains through Friday, and prepare for possible evacuation.
In Hiroshima Prefecture, the city of Hiroshima had record rainfall of 196 millimeters over 12 hours to 10 a.m. Thursday. The city of Takehara had 193 millimeters, also a record high, over half a day to around noon.
Active rainclouds are flowing in over Tottori and Hiroshima prefectures and elsewhere.
In Tottori Prefecture, 50 millimeters of rain was recorded over one hour to 3:30 p.m. on Thursday in Daisen Town. In neighboring Hiroshima Prefecture, the same amount was observed over one hour to 3:00 p.m. in Hatsukaichi City.
In Hiroshima Prefecture, a Level 5 alert urging residents to "secure safety immediately" was issued for parts of Mihara City. The alert level is the highest for heavy rain.
Weather officials are also warning of possible landslides for areas in Shimane, Tottori, Hiroshima, Yamaguchi and Hyogo prefectures.
The officials also forecast heavy thunderstorms mainly in western and eastern Japan through Friday.
They say the northern Kyushu region may have up to 120 millimeters of rain over 24 hours till noon on Friday.
They say the precipitation may reach 100 millimeters in Yamaguchi Prefecture and the Chugoku region, 80 millimeters in the Tokai region and 70 millimeters in the Hokuriku region.