2019 Volume 15A Pages i
In July 2018, heavy rainfalls occurred throughout the Japanese islands, especially in the western and central parts of Japan, under the influences of Typhoon Prapiroon (2018) and the Baiu frontal activity, and caused extreme river discharge, flooding, and landslides in many places and fatalities of greater than 200, which is the worst disaster in the recent three decades in Japan. After the heavy rainfall event, record-breaking, extremely hot weather follows. About a year before the heavy rainfall event, the July 2017 Heavy Rainfall event occurred in the northern part of Kyushu Island; long-lived stationary convective systems caused extreme rainfall, leading to flooding, landslides, and forest damages at local scales. Those extreme rainfalls in 2017 and 2018 result from linear convective systems that are a type of linearly organized mesoscale convective systems.
Such linear convective systems often develop under the influences of stationary fronts and tropical cyclones and have been investigated as case studies on specific extreme events; however, the behavior, maintenance mechanisms, and environmental properties of the linear convective systems have not been examined in detail. In addition, the heavy rainfall events throughout Japan in July 2018 were affected by various meteorological conditions with spatial scales ranging from planetary-scales to mesoscales, and thus integrated views at various scales are required. Furthermore, the impacts of climate change on the development of such extreme events should also be taken into account. In this special edition jointly coordinated with Journal of the Meteorological Society of Japan, we publish papers on generations of heavy rainfalls and extreme weathers, the properties and mechanisms of linear convective systems, predictability of heavy rainfall events and extreme weather, the impacts of climate change, focusing on recent extreme events such as the heavy rainfall events that occurred in Japan in July 2018 and the following extreme heat waves, the July 2017 Northern Kyushu Heavy Rainfall event, and other extreme weather phenomena not only in Japan but also in East Asia and other parts of the world.