South China Sea: Tropical Storm Chaba tracking northwestward in the South China Sea late July 1 /update 2

Event

Tropical Storm Chaba is tracking northwestward over the South China Sea as of late July 1. As of 20:00 CST, the system's center of circulation was approximately 330 km (205 miles) south-southwest of Hong Kong.

Forecast models indicate that the storm will strengthen into a typhoon as it generally tracks northwestward across the South China Sea early July 2 before making landfall over southeastern Guangdong Province, China mid to late July 2. The storm is forecast to weaken to a tropical storm after making landfall and will weaken further as it turns to track north across eastern Guangxi province July 3, becoming a tropical depression and then dissipating over northeastern Guangxi late July 3. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

As of late July 1, Chinese authorities have issued an orange (second-highest level on a four-tier scale) typhoon warning. The storm is expected to make landfall between Wuchuan and Xuwen counties in Guangdong Province July 2 and will be carrying winds of 108-126 kph (67-78 mph). Strong winds are also expected across Hainan Island, the coast of Guangdong Province, and the southeast coast of Guangxi Province. Heavy rains are likely over most of Guangdong, southeastern Guangxi, Hainan Island, and southwestern Fujian. The heaviest downpours are likely over northern Hainan Island and the southern and western coasts of Guangdong Province, with rainfall totals of 25-30 cm (10-12 inches) possible in these areas. Officials in Hong Kong have issued a No. 8 Southeast Gale or Storm Signal, with winds speeds of over 63 kph (39 mph) expected over the territory.

Vietnamese authorities have warned of strong winds and large waves along much of the east coast July 1-2. Large waves together with high tides could result in flooding in low-lying areas from Quang Ninh to Ninh Binh provinces. Heavy rainfall is expected in northeastern regions from late July 2, and will continue across northern and northeastern regions July 3-4. Daily rainfall totals of up to 35 cm (14 inches) are possible in parts of the affected area. Officials could update and possibly extend the coverage of the relevant weather alerts over the coming days.

Authorities in Hainan Province have closed the Haikou Xiuying, Railway South, and Xinhai ports through at least July 3. China's National Defense General Office has issued a level 4 emergency response (highest level on a four-tier scale) and sent two working groups to southern Guangdong Province to assist and guide typhoon prevention work.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. Localized evacuations, flash flooding, and landslides are possible if weather conditions prove hazardous.

The inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Raw sewage and other hazardous materials mixed with floodwaters pose 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
China Meteorological Administration
Vietnam National Centre for Hydro-Meteorological Forecasting