The role of westerly jet and Tibetan high during the heavy rainfall 2010 over Pakistan

Pakistan has been facing severe weather events since the last decade. Particularly, catastrophic flash floods in 2010, has affected badly a large populated area of the country. This extreme weather event is strongly associated with the westerly jet stream wind at 300 hPa and Tibetan high. The jet stream and Tibetan high play a dominant role to enhance the deep convection over Pakistan. In this study, the high-resolution mesoscale model such as Weather Research and Forecasting (WRF) model and the diagnostic variables are used for the detailed analysis of mesoscale convective system (MCS). The observed results show that the Tibetan high is slightly shift towards south west and westerly jet at 300 hPa towards southeast over Pakistan that produced strong convergence over the region. In addition, moisture transport over the Arabian Sea and Bay of Bangal along the foothills of Himalayan range play a significant role to enhance the convection over Pakistan that produced heavy rainfall. Thus, this study is very important for the forecasters to understand the nature of MCS when, where, and how it develops and maintains itself.