The centre said that at 4 am on September 17, the eye of the typhoon was located at 22.6 degrees north and 109.3 degrees east over the southern mainland of Guangdong province, China with the strongest winds reaching 75-100 km per hour.
Over the next 24 hours, the tropical depression will track west north-west at a speed of 15km per hour and further weaken into a low pressure system.
Forecasters said the system will bring rainstorms and rough seas to waters of the northern area of the Tonkin Gulf from September 17 and for the next 24 hours.
Due to the impact of the typhoon circulation, there will be heavy downpours in the north-eastern and north-western regions such as Lang Son and Cao Bang, Ha Giang, Lao Cai and Lai Chau from September 17-19.
Torrential rains will also affect northern localities and Thanh Hoa province.
Forecasters also issued warnings for flooding from several rivers such as the Red River, Thai Binh, Lo, Thao, Ky Cung and Bang Giang and said there is a risk of flash floods and landslides in northern mountainous provinces such as Quang Ninh, Lang Son, Cao Bang, Bac Kan, Ha Giang, Lao Cai, Yen Bai, Son la, Lai Chau.