Investigation of transition signals from single cell to multicell thunderstorms in the Kinki region, Japan by using vertical vorticity and multi-parameter radar analysis

Floods and landslides caused by extreme weather events, such as localized excessive rainfall in Japan, cause enormous devastation. Multicell clouds, on the other hand, have a common duration of over an hour and greater aerial coverage than single-cell clouds. For flood warning systems to function properly, the hazardous cloud must be detected quickly. Using pseudo and dual-Doppler vorticity approaches, the vertical vorticity estimate was extended from single-cell to multicell transitions case. According to the research, the single cells attained the peak of maximum vorticity of 0.08 and 0.01 s−1 for pseudo-vorticity and dual-Doppler vorticity, respectively. The maximum column of specific differential phase (Kdp) column above the melting layer indicated that the transition with 1 km depth as compared to differential reflectivity (Zdr) column was not observed after the cell merging. However, it was identified 5 min after the cell merged. In contrast, the Kdp column was always identified after the cell merging, and the column showed an increase in intensity 5 min after the cells merged. Vertical vorticity and multi-parameter radar analysis provided an insight into the transition from single-cell to multicell formation.