South China Sea: Tropical Depression 16W tracking northwestward off the coast of central Vietnam as of early Oct. 18 /update 1

Event

Tropical Depression 16W is tracking northwestward across the South China Sea, off the east coast of central Vietnam, early Oct. 18. As of 10:00 ICT, the system's center of circulation was approximately 159 km (99 miles) east-northeast of Da Nang.

Forecast models indicate that the storm will maintain its strength and make landfall over the southwestern edge of Hainan Island, China, late Oct. 18-early Oct. 19. The system is forecast to briefly strengthen into a tropical storm as it reaches the Gulf of Tonkin Oct. 19 before the storm turns to track sharply southwestward early Oct. 20. The system is forecast to weaken back into a tropical depression early Oct. 22 as it continues southwestwards and will likely dissipate early Oct. 23 before it reaches the north-central Vietnam coast. 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 a warning bulletin for the storm system, advising that heavy to very heavy rainfall is likely from Quang Tri to Quang Nam provinces and moderate-to-heavy rainfall in Ha Tinh, Quang Tri, and Quang Ngai provinces Oct. 18-early Oct. 19. Further heavy rainfall is likely in northeastern and north-central regions from late Oct 19. Heavy rainfall in the mid-central region is likely to ease from late Oct. 19. Rough seas are also forecast in coastal areas over the coming days. The China Meteorological Administration has issued a blue rain warning (the lowest level on a four-tier scale); heavy rainfall is forecast in central and western Guangdong, southeastern Guangxi, and Hainan provinces, with the heaviest rainfall of 10-16 cm (4-6 inches) likely in the coastal areas of southwestern Guangdong Province and eastern Hainan Island. Heavy rainfall and rough seas are forecast over the coming days.

Heavy rainfall in recent days has caused flooding in parts of central Vietnam. The inclement weather has displaced more than 7,600 people in Da Nang and Thua Thien Hue provinces and damaged more than 1,600 homes, predominantly in Da Nang City. Authorities have also reported that 15 fishermen are missing after two vessels capsized off the coast of central Vietnam.

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.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

Joint Typhoon Warning Center (JTWC)
Vietnam National Center for Hydrometeorological Forecasting (NCHMF)