Synopsis

Japan is experiencing an increasing frequency of localized downpours, often torrential in intensity. The resulting flash floods overwhelm rivers and pose a serious threat to homes and lives. These sudden storms have historically proven difficult to predict, owing to the brief interval between the development of towering cumulonimbus clouds and the arrival of the rain. However, a new type of radar, known as phased-array radar, coupled with simulations run on a Japanese supercomputer, now promises