At 10am Lionrock is about 100km off the northern port city of Hai Phong, packing sustained winds of 60-75kph near its centre.
The storm is forecast to change its direction a bit into west and southwest and weaken into a tropical depression before battering the southern part of the Red River Delta and north-central localities.
Together with a cold front which is moving from north to south, Lionrock will cause strong winds and heavy rain in large parts of northern and north-central regions, with average rainfall of 100 - 250mm.
The national weather forecasting bureau warned of a high risk of flash floods and landslides in mountainous areas and flooding in low-lying and riverside areas.
Meanwhile, another tropical storm Kompasu is churning through the southern part of the Philippines and is anticipated to enter the East Sea on October 11.
Initial forecasts show after moving into the East Sea, Kompasu will quickly increase its intensity and is likely to affect northern and north-central provinces of Vietnam on October 13-15.
Another tropical depression or storm is likely to form in the East Sea and is forecast to affect Vietnam several days later.
Weather forecasters warned the northern and north-central provinces will experience heavy downpour over the next 10 days.
Provinces from Hai Phong to Quang Binh have already ordered fishing vessels to move ashore or seek storm shelters to avoid Lionrock’s track. They have also made plans to evacuate local residents from low-lying areas to a higher ground.
Search and rescue forces of these localities have been on standby in case of emergency. The Ministry of Defence said it will deploy 380,000 troops and more than 3,000 vehicles and helicopters to support search and rescue work.
