Investigation of Flash Flood Producing Rainstorm in Northeast Bangladesh Using WRF Model

Abstract

Flash flood events occur in the northeastern region of Bangladesh when convective cells assemble into a mesoscale convective system (MCS) over the steep edge of the plateau. On 17 and 18 April 2010, a flash flood, caused by rainstorm over Meghalaya plateau, inundated the low-lying regions (locally known as Haors) of northeastern Bangladesh. Prediction of this sudden incident is challenging when it happened on the high terrain of Meghalaya plateau and adjoining Bangladesh. This study investigated the synoptic flow patterns and numerical features of the flash flood-producing storm and its associated tropospheric conditions in northeast Bangladesh using the Weather Research and Forecasting (WRF) model. The study revealed that the 48-h simulated rainfall was about 152 mm for outer domain-1, 195 mm for inner domain-2 and 209 mm for the innermost domain-3 whereas actual rainfall was 223 mm as recorded by BMD. For instance, in convection resolving resolution at 9 km and 3 km domain, the model error was 12.3% and 5.9% respectively.