Japan: Adverse weather forecast across western regions through at least March 26

Severe weather is forecast across parts of western Japan through at least March 26. As of March 25, the Japan Meteorological Agency (JMA) has issued a severe weather bulletin warning a weather front moving eastward across the region will bring heavy rainfall, thunderstorms, strong winds, lightning, and possible tornadoes in parts of western Japan and the Pacific coast of eastern Japan; residents should be vigilant for landslides, flooding, and rising river levels. Forecast models indicate rainfall totals of around 15 cm (6 inches) are possible in the Izu Islands and northern Kyushu Region through late March 26 and around 12 cm (5 inches) in Kinki, Shikoku. and southern Kyushu regions. As of March 25, red evacuation of elderly people and other vulnerable groups warnings (the middle level on a five-tier scale for evacuation warnings) have been issued for nearly 6,000 people across Yatsushiro City in Kumamoto Prefecture due to the threat of landslides.

As of March 25, the JMA has issued the following weather warnings across the affected area:

• Yellow heavy rain and landslide warnings (the lowest level on a four-tier scale): Across Ehime and Kumamoto prefectures and parts of Miyazaki, Nagasaki, and Oita prefectures.

• Yellow gale/strong wind warnings: Across Kagoshima, Nagasaki, Saga, and Shimane prefectures and parts of Fukuoka, Kumamoto, and Yamaguchi prefectures.

• Yellow high wave warnings: Across the Izu Islands, Kagoshima Prefecture, Nagasaki Prefecture, and Shimane Prefecture and parts of Fukuoka, Kumamoto, Oita, Saga, and Yamaguchi prefectures.

• Yellow thunderstorm warnings: Across northern Kyushu, southern Kyushu, and Shikuoka regions and parts of the Izu Islands and Hiroshima, Hyogo, Mie, Nara, Okayama, Osaka, Shimane, and Wakayama prefectures.

• Yellow dense fog warnings: Across the Izu Islands, Fukuoka Prefecture, Mie Prefecture, Osaka Prefecture, and Saga Prefecture and parts of Hyogo, Nagasaki, and Tokushima prefectures.

Officials will likely issue new alerts or update/rescind existing advisories as weather conditions develop over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil. Disruptions to electricity and telecommunications services are possible where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows could render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger intermittent flight delays and cancellations at airports across the affected region, though these are unlikely to be severe or prolonged. Authorities may temporarily suspend port operations or close beach fronts if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation. Localized business disruptions may occur in low-lying areas.