Application of NWP Model in Prediction of Heavy Rainfall in Bangladesh

During 8-9August of 2011 wide spread heavy rainfalls occurred in Bangladesh. WRF model with the grid resolution of 9 km is used to diagnosis the events for detecting the insight physical processes. Analysis reveals that a low pressure system initiated over southwestern part of Bangladesh (Khulna and Satkhira regions & adjoining North Bay) at 0300UTC of 8August 2011 and moved north/northeastwards and intensified into a Depression. Then it recurved northwestwards and located over Rajshahi region and its adjoining areas of Bangladesh at 0000UTC of 9August 2011 and moved slowly westward further to West Bengal of India. After reaching to West Bengal of India and adjoining western part of Bangladesh the central pressure of the system dropped off rapidly and intensified once more into a Deep Depression. The system weakened gradually afterward by giving precipitation. During the life cycle of the system the pressure, wind, humidity, vorticity fields were very much supportive for generating high intensity rain bands over Bangladesh and adjoining north Bay of Bengal and high amounts of rainfall over Bangladesh on 8August 2011 on the basis of initial and boundary conditions of 0000UTC of 8August 2011 which comply with the observation but it could not captured strong rain bands for 9August 2011. But model captured the high intensity rain bands for 9August 2011 with the delayed initial conditions of 0000UTC of 9August 2011.