The National Civil Defence Steering Committee issued the warning on September 8, calling on coastal localities to closely monitor weather developments and take measures to protect people, vessels and property.
According to the Department of Hydrometeorology under the Ministry of Agriculture and Environment, a tropical convergence zone is expected to form over the East Sea from September 9, with its axis extending across the central region.
A tropical depression is highly likely to develop over the central East Sea around September 12-13 and could subsequently strengthen into a storm.
The northern Gulf of Tonkin is forecast to see northeasterly winds of force 5, occasionally reaching force 6, with waves of two to three metres.
Central Vietnam is expected to experience widespread moderate to heavy rain from September 10 to 17, raising the risk of tornadoes, lightning, flash floods, landslides and localised flooding.
Meanwhile, the northern and central East Sea, including the Truong Sa (Spratly) Special Zone, could see tornadoes and wind gusts of force 7-8 on September 8, with waves exceeding two metres.
Coastal localities from Quang Ninh to An Giang have been instructed to keep fishing vessels and other boats informed of weather warnings and help them adjust operations to ensure the safety of crews and property.
Authorities have also been asked to closely monitor vessels, particularly tourist boats operating in bays, coastal waters and around islands, and maintain communications to respond promptly to emergencies.
In central Vietnam, local authorities should closely track forecasts for heavy rain and other hazardous weather, promptly warn residents and evacuate people from areas at high risk of severe flooding, flash floods and landslides when necessary.
Local response forces should also remain ready to assist affected communities, while public information campaigns should provide residents with guidance on dealing with heavy rain, lightning, flash floods, landslides, flooding, tropical depressions and strong winds at sea.
The committee also asked the 21 provinces and cities to maintain round-the-clock emergency duty and regularly report developments to national authorities.