Japan Meteorological Agency confirms rainy season onset in western prefectures
The Japan Meteorological Agency declared the start of the tsuyu season for northern Kyushu, the Chugoku and Kinki regions on June 4, following days of adverse weather conditions and prior disaster warnings in southern Japan.
The Japan Meteorological Agency announced on the morning of June 4 that the rainy season, known locally as tsuyu, has likely begun in northern Kyushu, the Chugoku region, and the Kinki region. The declaration follows persistent rainy and cloudy weather across western Japan, driven by a frontal system and moist air.
The agency’s assessment comes shortly after heightened disaster risks in southern Japan. On June 3, the Japan Meteorological Agency issued a 'linear rainband imminent prediction' weather disaster warning for southern Wakayama, Mie, and Tokushima prefectures, citing a high probability of linear rainband formation within three hours.
Concurrently with the June 3 warning, an 'emergency safety assurance' order was issued for 31 households, comprising 63 people, in the Chosei district of Anan, Tokushima. This measure was taken in response to the heightened disaster risk posed by the developing weather systems.
Atmospheric conditions in Kyushu are forecast to remain highly unstable through June 5. The Japan Meteorological Agency’s use of the phrasing "likely begun" indicates that the declaration is based on current observations and probabilistic assessment rather than absolute certainty.
The onset of the rainy season marks a significant shift in weather patterns for the affected regions, with authorities continuing to monitor the stability of the atmosphere as the frontal system persists.
