Abstract
The North-Eastern (NE) region of Bangladesh is subject to recurring flash floods as a result of extreme rainfall in India's Meghalaya region. However, the flood in 2022 far exceeded previous devastations, inundating approximately 80% of Sylhet and Sunamganj districts in response to Cherapunjee's 102-year record rainfall. The three-day and five-day lead time forecasts showed an underestimation of forecasts during the flash flood period, which is a common problem with flash flood forecasting around the world. We investigated the presence of the Atmospheric River to see if there is a relationship between the Atmospheric River (AR)'s landfall and extreme precipitation, which could help to forecast extreme precipitation. An atmospheric river landfall was detected on June 15, 2022, at 12 a.m., and the three-day cumulative rainfall from June 15 to 17 exceeded 2500 mm. Windspeed and geopotential height analysis revealed the presence of a Low-Level Jet across the Pacific Ocean toward the NE region of India and Bangladesh, shifting a lot of moisture in the upper atmosphere to the area that generated the atmospheric river. Therefore, AR detection and monitoring should be integrated into the Meghna basin's flood forecasting system.