Atmospheric Rivers are evolved through the interaction of meteorological phenomena with oceanic, wind, and solar conditions. The monsoon in the Indian subcontinent is predominantly influenced by the Inter Tropical Convergence Zone (ITCZ), which is created as a result of the location of the sun. The prevailing eastward wind carries moisture from the equatorial region to the tropical regions. Furthermore, the fluctuation in temperature leads to the formation of a zone with lower atmospheric pressure over the land, while an area with higher atmospheric pressure develops over the water. As a result, this difference in pressure causes the movement of winds carrying moisture from the Arabian Sea and Bay of Bengal towards the land. The recurring occurrence of this climatic phenomenon leads to the onset of the monsoon season in India and its neighboring countries. Nevertheless, certain climatic variables, such as the occurrence of La Nina, can intensify the monsoon wind, leading to a substantial enhancement of precipitation in these specific regions [35]. Consequently, a substantial amount of heavy rainfall events has been recorded from 2019 to the present. The intense and extended rainfall might overpower the local drainage systems and saturate the soil, heightening the likelihood of flash floods. As a result, ARs are frequently linked to severe weather occurrences and can significantly affect local hydrology and water resources. Moreover, recent studies suggest the existence of ARs in the Bay of Bengal area, which leads to intense precipitation and consequent floods in these locations [36-40]. In addition, the ARs generated in the high-pressure area of the Arabian Sea traverse India and result in significant orographic precipitation in the Himalayan region, particularly in Nepal [41]. Furthermore, due to the Onset of the monsoon in the Indian subcontinents, the South West monsoon usually arrives in late May, and moisture from the Arabian Sea as well as the Bay of Bengal is supplied towards the low-pressure land area zone. The intense moisture transport is obstructed by the Western Ghats on the coast of South India and generates immense rainfall and flooding. Recent studies have shown the link between extreme rainfall and flooding in Mumbai and other coastal areas on the left bank of India with Atmospheric Rivers that are generated due to the presence of low-level jets and immense moisture supply from both the Arabian Sea and the Bay of Bengal [42-45]. Additionally, the relation of extreme precipitation in Chennai and other South Indian regions with the presence of the Atmospheric River has been established [46], [47]. However, the contribution of AR in generating extreme rainfall in the Meghalaya region that generates severe flash floods in the North Eastern (NE) region of Bangladesh has not been thoroughly studied.
Therefore, the objective of this study is to evaluate the accuracy of the forecasting provided by the FFWC during the extreme flood in the Meghna basin in 2022, and to investigate the influence of the atmospheric river on the extreme rainfall at Cherapunjee in June 2022 by detecting its formation in this region.