The National Centre for Hydro-Meteorological Forecasting said that in the early hours of September 12, a low-pressure area over waters to the south-west of the Hoang Sa special zone had strengthened into a tropical depression.
Early this morning, the tropical depression was packing winds of force 6, with gusts up to force 8, about 150 kilometres south-west of the Hoang Sa special zone.
Forecasters said the system was moving north-west at about 10 kilometres per hour towards waters stretching from Ha Tinh to Quang Ngai.
According to the meteorological agency, by about 4 am on September 13, the tropical depression will shift to a north-westerly track and remain active over waters off Hue-Danang. By about 4 am on September 14, it is expected to turn west-north-west and move over coastal waters from Ha Tinh to Hue.
The tropical depression is heading towards waters off central provinces (Photo: NCHMF).
Between 48 and 72 hours later, the tropical depression is forecast to continue moving west-north-west at around 10 kilometres per hour before gradually weakening into a low-pressure area.
Under the influence of the tropical depression, waters to the west of the Hoang Sa special zone and waters from Ha Tinh to Quang Ngai are forecast to see force 6 winds, gusting to force 8, with waves of 2 to 4 metres and rough seas.
Vessels operating in the hazardous areas mentioned above face the risk of thunderstorms, whirlwinds, strong winds and high waves.
The meteorological agency said that overnight and in the early hours of this morning, areas from southern Quang Tri Province to Quang Ngai, and eastern parts of provinces from Gia Lai to Dak Lak, saw moderate to heavy rain and thunderstorms, with some places recording very heavy rainfall.
From early morning until tonight, areas from Ha Tinh to northern Quang Tri Province are forecast to experience moderate to heavy rain and thunderstorms, with rainfall of 40 to 80mm, and some places exceeding 150mm.
Areas from southern Quang Tri Province to Quang Ngai, from southern Nghe An Province to Danang, and from Thanh Hoa to northern Nghe An Province are also forecast to see heavy to very heavy rain accompanied by thunderstorms.
In addition, during the day and night of September 12, eastern parts of provinces from Gia Lai to Lam Dong, the Central Highlands and southern Vietnam are forecast to have rain, moderate rain and scattered thunderstorms, with rainfall of 20 to 40mm and some places exceeding 80mm.
Further ahead, the meteorological agency said that during the day and night of September 14, the northern midlands and Red River Delta, along with southern parts of Son La, Tuyen Quang and Lao Cai provinces, are forecast to see moderate to heavy rain and thunderstorms, with rainfall of 30 to 60mm and some places exceeding 100mm.
Areas from Thanh Hoa to Quang Tri are forecast to receive heavy to very heavy rain and thunderstorms, with rainfall of 70 to 150mm and some places exceeding 250mm.
Heavy rain in these areas may persist until the morning of September 16.