Two tropical depressions formed in the waters south of Japan on July 1 [1], raising the possibility of a double typhoon event.
This development is critical because the interaction between two simultaneous storms can create unpredictable weather patterns and intensify rainfall. The Japan Meteorological Agency (JMA) is monitoring the systems to determine if they will mutually influence each other as they move toward the mainland.
The JMA said these two tropical depressions could develop into typhoons within the next 24 hours [4]. The agency has issued warnings for five regions, Kyushu, Shikoku, Kinki, Tokai, and Kanto-Koshin, where warning-level heavy rain is expected on July 2 [3].
Instability has already begun affecting various parts of the country. In Imari City, Saga Prefecture, rainfall reached 43 mm per hour [2]. In Tokyo, guerrilla thunderstorms occurred on July 1, while a reporter in Kitamoto City, Saitama Prefecture, said heavy rain struck building roofs after 4 p.m. [5].
Meteorologists are closely watching the Philippine Sea area where the depressions originated. The simultaneous presence of these systems increases the risk of flooding and landslides across the affected regions. Local authorities said residents should remain vigilant as the systems evolve into full-fledged typhoons [4].
“Two tropical depressions could develop into typhoons within the next 24 hours.”
The potential for a 'double typhoon' increases atmospheric instability and complicates forecasting, as two rotating systems can alter each other's trajectories and intensity. For Japan, this means a broader geographic area is at risk of simultaneous flooding and wind damage, placing higher stress on emergency response resources across five distinct regions.
