South China Sea: Tropical Storm Nalgae tracking north-northwest across the South China Sea late Nov. 2

Event

Tropical Storm Nalgae is tracking north-northwest across the South China Sea late Nov. 2. As of 20:00 CST, the system's center of circulation was approximately 187 km (116 miles) southeast of Hong Kong.

Forecast models indicate that the storm will weaken as it tracks northwestward and passes over the Wannshan Archipelago in Guangdong Province, China, early Nov. 3. Nalgae is then forecast to weaken into a tropical depression as it tracks west-southwestward off the southern coast of Guangdong Province Nov. 3, passing near or over the Chuanshan Archipelago late Nov, 3. . The system is expected to turn to track southwestward away from the coast and dissipate early Nov. 4. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

As of late Nov. 2, the China Meteorological Administration has issued a blue (the lowest-level on a four-tier scale) typhoon warning; heavy rainfall of 5-6 cm (2-2.4 inches) is forecast near the mouth of the Pearl River in Guangdong Province and its eastern coast late Nov. 2-late Nov. 3. The Hong Kong Observatory has issued Typhoon Warning Signal No. 8 through early Nov. 3 due to the approach of the storm. Officials will likely update and extend the coverage of the relevant weather alerts over the coming days as the system progresses.

Authorities have activated an emergency level 4 response (the lowest level on a four-tier scale) for Guangdong, Hainan, Fujian, and Guangxi provinces due to the passage of the storm. Authorities in Hong Kong have suspended classes, ferries, and bus services as of Nov. 2 and the stock exchange canceled the afternoon trading session.

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. Further flight disruptions at regional airports and temporary closures of ports are also possible. 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 typhoon or 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
China Meteorological Administration