At 4 pm on August 24, the storm's centre was about 130 kilometres southeast of Quang Ninh and 115 kilometres southeast of Haiphong, according to the National Centre for Hydro-Meteorological Forecasting.
Maximum sustained winds near the centre were at levels 8-9, or 62-88 kilometres per hour, with gusts reaching level 11. The storm was moving south-southwest at about five kilometres per hour.
By 4 pm on August 25, Narra is forecast to turn south-southeast, moving at around five kilometres per hour over the eastern Gulf of Tonkin, with winds of levels 8-9 and gusts of level 11.
The storm is then forecast to turn north-northeast and accelerate to 5-10 kilometres per hour towards the coast of China's Guangxi region on August 26, weakening into a tropical depression.
Over the Gulf of Tonkin, winds are forecast at levels 6-7, strengthening to levels 8-9 near the storm's centre, with gusts of levels 10-11. Waves could reach three to five metres near the centre.
Coastal areas of Quang Ninh, Haiphong and Hung Yen could see winds of level 6 and gusts of level 8 on Monday evening.
The storm's circulation is also expected to bring heavy rain to the southern Red River Delta and areas from Thanh Hoa to Ha Tinh from Monday evening through Tuesday morning, with rainfall of 50-100 mm and more than 180 mm in some areas.
Heavy rain could trigger urban and low-lying flooding, flash floods and landslides in mountainous areas, while thunderstorms, tornadoes and strong gusts are also possible.
Water levels on several rivers in northern and north-central Vietnam remain high. At 4 pm on Monday, the Trung River at Huu Lung in Lang Son stood at 21.56 metres, 2.56 metres above the highest warning level, and was still rising slowly.
The river is forecast to peak at around 21.9 metres on Tuesday morning, about 2.9 metres above the highest warning level, before receding.
