Accoridng to the National Centre for Hydro-Meteorological Forecasting, Thanh Hoa to Ha Tinh would see moderate to heavy rain and thunderstorms on September 18, with rainfall of 20-50mm and more than 80mm in some areas.
The rain belt is forecast to move south overnight and on September 19, bringing 30-60mm of rain from Nghe An to Hue, with some areas receiving more than 100mm.
Rainfall could exceed 100mm within three hours, increasing the risk of flooding in low-lying areas, cities and industrial zones.
Moderate rain and thunderstorms are expected to persist from Ha Tinh to Hue from the night of September 19 into September 20, with rainfall of 20-40mm and more than 80mm in some places.
Northern Vietnam is forecast to receive scattered showers and thunderstorms on September 18, with rainfall of 10-30mm and more than 50mm in some areas.
Southern Vietnam will see moderate rain and thunderstorms in the afternoon and evening, with rainfall of 20-40mm and more than 80mm in some places.
The Central Highlands, Khanh Hoa Province and eastern Lam Dong Province are forecast to receive scattered showers and thunderstorms, with rainfall of 10-30mm and locally more than 60mm.
Thunderstorms could bring tornadoes, lightning, hail and strong gusts, forecasters warned.
At sea, scattered showers and thunderstorms are forecast across the Gulf of Tonkin and waters from Lam Dong to Ca Mau, Ca Mau to An Giang, the Gulf of Thailand and parts of the East Sea, including the Hoang Sa and Truong Sa areas.
Tornadoes and gusts of force 7-8 could occur during thunderstorms, with waves exceeding two metres. Vessels operating in affected waters have been advised to closely monitor weather forecasts.
Hanoi will remain cloudy with occasional showers and thunderstorms, with temperatures ranging from 23 to 29 degrees Celsius.
HCM City is forecast to see showers and thunderstorms, with moderate to very heavy rain possible in the afternoon and evening. Temperatures will range from 24 to 33 degrees Celsius.
