18 Jul 2021 | 06:52 PM UTC
South China Sea: Tropical Depression 10W forms south of Hong Kong late July 18; landfall likely near Yangjiang, China, late July 20
TD 10W forms in South China Sea late July 18. Landfall forecast as tropical storm near Yangjiang, China, late July 20.
Event
Tropical Depression 10W has formed in the South China Sea during the evening of July 18. As of 20:00 CST, the system's center of circulation was approximately 196 km (122 miles) south-southwest of Hong Kong. Forecast models indicate the system will strengthen to a tropical storm as it tracks west-northwestward toward the Chinese coast over the coming days. The storm is forecast to make landfall as a tropical storm near Yangjiang, Guangdong Province, late July 20. Following landfall, will weaken as it follows the Guangdong Province coastline before veering sharply to the southeast and heading back out to sea, transiting northeast of Hainan Province. Significant uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.
Government Advisories
As of late July 18, the China Meteorological Administration has issued a blue level storm warning for coastal areas of central and southern Guangdong Province, indicating that winds of up to 50 kph (31 mph) are expected within 24 hours. Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the storm's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards; this is especially true in areas previously impacted by earlier tropical systems this season.
Hazardous Conditions
Tropical Depression 10W will bring heavy rainfall, strong winds, and storm surge across the affected area through at least July 22. Impacts will likely be felt across southern Guangdong, southeastern Guangxi, and Hainan provinces. Forecast models indicate 10-15 cm (4-6 inches) of rainfall are possible across coastal areas of southern Guangdong.
Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Rain-induced landslides are possible in steeply sloped terrains. Flooding could isolate some communities for several days. Prolonged swells and storm surge generated by the system will likely result in coastal flooding as the system approaches land. A persistent onshore flow could make it difficult for the surge to recede and water levels to decrease in coastal river catchments.
In addition to the heavy rain, flooding, and storm surge, the system could produce damaging wind gusts as it moves across China's far southeastern provinces. Tropical storm-force wind gusts over 50 knots (93 kph, 58 mph) cannot be ruled out. Localized power outages due to uprooted trees and toppled utility lines are possible.
Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least July 22. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports.
Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.
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 high potential for 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 in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Keep any necessary medications in a waterproof container.
Plan accordingly for commercial, transport, and logistics disruptions in areas in the path of the storm. 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.
