South China Sea: Tropical Depression 16W tracking west-southwestward in the South China Sea as of early Sept. 19 /update 1

Tropical Depression 16W is tracking westward across the South China Sea towards central Vietnam early Sept. 19. As of 04:00 ICT, the system's center of circulation was approximately 232 km (144 miles) northeast of Da Nang, Vietnam.

Forecast models indicate that the storm will maintain its strength as it tracks westward and makes landfall over Quang Binh Province in central Vietnam early Sept. 20. The system will weaken further and dissipate as it tracks westward over Khammouane Province in Laos the afternoon of Sept. 20. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

Vietnam's National Center for Hydrometeorological Forecasting (NCHMF) has issued an emergency warning for the storm system, advising that rough seas, storms, and strong winds are expected over the sea off central Vietnam over the coming days. Strong winds are expected in coastal areas from Ha Tinh to Quang Ngai provinces from early Sept. 19. Heavy rainfall is forecast in parts of central and northern Vietnam early Sept. 19-20, with rainfall totals of 10-30 cm (4-12 inches) likely and localized amounts of over 50 cm (20 inches) possible. Lesser amounts of 2-4 cm (0.8-1.6 inches) with localized higher totals of over 7 cm (3 inches) are expected in the Central Highlands and southern regions. Storm surges of 30-50 cm (12-20 inches) from Quang Binh to Quang Nam provinces, together with high tides and large waves, may result in landslides and flooding in low-lying areas.

Authorities in Quang Binh have imposed a ban on all maritime activities and instructed all vessels to seek shelter. Much of northern Vietnam is still recovering from the passage of Typhoon Yagi, which resulted in at least 298 fatalities and 35 others still missing. The system made landfall over Quang Ninh Province the afternoon of Sept. 7, before weakening into a tropical storm and then dissipating as it moved west-northwestward over northern Vietnam through Sept. 8.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible. The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.