Evolution of Mesoscale Convective Complex and Its Atmospheric Conditions During Heavy Rain in Bandung, 22 February 2018

Abstract

AbstractOn February 22, 2018, there was a flood due to prolonged heavy rain in the Bandung Regency area (eastern part), which was identified as having a mesoscale convective complex. This paper describes the mesoscale convective complex that causes the flood and analyzes several weather parameters and conditions of global atmospheric phenomena when there are mesoscale convective clouds. The data used are rainfall data from GSMaP, cloud data from Himawari-8, and weather parameter data from ECMWF ERA-Interim. This study indicates that the rainfall at the time of the flood is included in the category of weighty rain caused by the mesoscale convective complex. The MCC began to develop from around 1600 LST from small clouds triggered by the convergent flow of inland winds that continued to grow and develop into a maximum-scale MCC. At 1900-2000 LST and decayed at midnight (2100-0100 LST). The formation of mesoscale convective clouds is supported by atmospheric conditions in divergence, vorticity, and vertical motion. The high specific humidity in the study area also allows the formation of convective clouds that produce heavy rain. There are convergent surface wind flows as the local convergence but not related with land breeze triggered the development of some of the clouds over Bandung Regency and its surrounding area. At the same time, the strong southerly wind on the surface triggered the development of this MCC. During MCC, reach the maximum stage, there is an upward with a high enough specific humidity that allows the formation of convective clouds that cause rain. At the same time, the vorticity in Bandung Regency, the level of 700 hPa, was negative. Several new convective systems were generated during the MCC decay stage at midnight due to the cold pool formed under the MCC system, which made the temperature under the MCC system very cold compared to the surrounding temperature.KeywordsMesoscale convective complexHeavy rainAtmospheric condition