Heavy Rain Expected Across Japan on the 18th, with Potential for Linear Rainbands in Kyushu and Shikoku

The Japan Meteorological Agency announced on the 17th that atmospheric conditions are likely to become unstable from the Amami Islands to eastern Japan on the 18th, potentially leading to heavy rain accompanied by thunderstorms. They urged the public to exercise caution. The agency issued a "half-day advance forecast" for the southern part of Kyushu, including Kagoshima Prefecture (excluding Miyazaki Prefecture and the Amami Islands), and the four prefectures of Shikoku, warning of the possibility of a linear rainband. There is a risk that the danger of landslides and river flooding could rapidly increase by the morning of the 18th.

Furthermore, the Japan Meteorological Agency announced on the 17th that northern Kyushu, including Yamaguchi Prefecture, appears to have entered the rainy season. This is 13 days later than usual and 19 days later than last year. According to the Meteorological Agency, a front extends from the Chinese mainland through southern Kyushu to the south of Japan. A low-pressure system along the front is developing and moving northeastward from western Japan towards the Pacific side of eastern Japan.

The Japan Meteorological Agency particularly emphasized the need for caution regarding heavy rain in the Kyushu and Shikoku regions, citing the possibility of a linear rainband. A linear rainband is a formation of long stretches of powerful rain clouds, which can trigger torrential downpours within a short period, potentially leading to severe consequences like landslides, river flooding, and other serious damage.

In addition to the possibility of a linear rainband, the Japan Meteorological Agency is forecasting a wide range of areas with a high probability of heavy rain on the 18th. The Kyushu and Shikoku regions have already entered the rainy season, and the 18th poses an increased risk of heavy rain due to the potential for a linear rainband. Consequently, it is crucial to be extremely cautious about potential heavy rain damage. Moreover, there is a risk that the danger of landslides and river flooding could rapidly increase by the morning of the 18th, necessitating thorough preparation for safety measures in advance.

The Japan Meteorological Agency will continue to issue forecast information and promptly disseminate the latest information to the public.

This heavy rain is expected to occur due to the activation of the Baiu front (the rainy season front) and the influx of moist air. In particular, linear rainbands are a weather phenomenon that is difficult to predict. They can occur suddenly and cause significant damage. Therefore, it is important to pay close attention to heavy rain forecasts and take thorough precautions in advance.