1. Extremely strong Cyclone "MOCHA" made landfall in Rakhine State in western Myanmar, with a maximum wind speed of more than 200 kilometers per hour. Heavy rain and waves were seen along the coast of Rakhine State, and strong winds and rain hit Nay Pyi Taw, Irrawaddy, Yangon and Tanintharyi provinces, as well as river surges and flash floods in mountainous areas such as Chin State.
2.The Bay of Bengal, as an area with frequent Asian summer monsoon activities and the strongest rainfall, is an important water vapor source for precipitation in China and a key area for water vapor transport southward of floods in China. The impact of the Gulf storm on China's weather was mainly concentrated in Yunnan-Guizhou Plateau and Qinghai-Tibet Plateau, especially in southern Tibet and southwestern Yunnan. After the landfall of the Bay of Bengal, it interacts with favorable atmospheric environment flow fields (such as the southern branch trough, subtropical high, etc.), forming a strong southwest airflow, transporting water vapor from the Bay of Bengal to China, which can produce precipitation in southwest China. The southwest water vapor transport generated by the the Bay of Bengal Storm provided favorable water vapor conditions for sustained heavy precipitation in the southwest. Therefore, the storm may cause long-term rainfall in Guangxi, Guangdong, Hainan and other places. Motuo, Mangkang, Basu and other places may have heavy rain, high altitude areas may have heavy snow.
3.The strong ocean-land-air interaction in the northern Indian Ocean and tropical Asia in spring is an important reason to stimulate the occurrence of the vortex in the Bay of Bengal. The intra-seasonal-oscillation of the tropical atmosphere (ISO) can modulate the generation of storms in the Bay of Bengal. Due to the cyclonic circulation, boundary layer convergence and abundant water vapor caused by the northward spreading ISO, the intensity of tropical cyclones can develop rapidly, and there is a high possibility of stronger tropical cyclones in the Bay of Bengal in April and May.
4.Due to the flared shape of the Bay of Bengal, storms generated in the Bay of Bengal or transferred from the South China Sea through the Indochina Peninsula are prone to land in the coastal areas of the sea. Storms in the Bay of Bengal are mostly generated in the central and northern Bay of Bengal, and the monthly changes of storm frequency, average and longest duration are bimodal distribution.