The Japan Meteorological Agency warns of intense rain and thunderstorms across East Japan and Tōhoku through Wednesday morning [1].
These diverging weather patterns pose immediate risks to public safety, ranging from potential landslides and river overflows in the north to heat-related illnesses in the south.
Forecasters said warm, moist air is colliding with cold air aloft, creating strong atmospheric instability [1]. This interaction is expected to produce localized, torrential rainfall that may resemble waterfalls in some areas [2].
Regional rainfall predictions for the 24-hour period starting Tuesday at 06:00 include 150 mm in the Hokuriku region [1]. The Kanto-Kōshin and Tokai regions are both expected to see 120 mm [1], while the Kansai region is forecast for 100 mm [1]. Tōhoku is predicted to receive 80 mm [1].
Authorities are advising residents in these areas to remain vigilant regarding road flooding and the risk of landslides [1].
Meanwhile, West Japan, including the Kansai, Chūgoku, and Kyushu regions, is experiencing a different crisis. The region remains largely sunny with extreme heat continuing [2]. Maximum temperatures in parts of West Japan are expected to reach 35 °C or higher [1].
"West Japan will widely be sunny and intense heat is likely to continue," MSN Japan said [2].
“The Kanto-Kōshin and Tokai regions are both expected to see 120 mm.”
The simultaneous occurrence of extreme precipitation in the east and a severe heatwave in the west highlights the volatility of Japan's summer weather. The high volume of predicted rainfall in the Hokuriku and Kanto regions increases the likelihood of infrastructure failure and geological instability, while the persistent heat in the west places a heavy burden on the public health system and energy grid.
