South China Sea: Tropical Storm Cempaka tracking westward in southwestern Guangdong as of early July 21 following landfall near Yangjiang /update 4

Event

Tropical Storm Cempaka is tracking westward in southwestern Guangdong Province, China, as of early July 21 after making landfall south of Yangjiang. As of 02:00 CST, the system's center of circulation was approximately 296 km (184 miles) west-southwest of Hong Kong. Forecast models indicate the tropical storm will weaken into a tropical depression by early July 22 as it tracks generally westward. The system is forecast to shift southward and then southeastward as it transits over the Gulf of Tonkin before strengthening into a tropical storm and making another landfall near Danzhou on the northwestern coast of Hainan. The system is forecast to then weaken as it transits eastward and then northeastward over the northern South China Sea from July 25. Significant uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

Government Advisories
As of early July 21, the China Meteorological Administration has maintained its orange-level typhoon warning (i.e., the second-highest level in a four-tiered system) for coastal areas of central and western Guangdong Province, as well as coastal areas of Guangxi and Hainan, indicating that winds of up to 137 kph (85 mph) are possible in some areas 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 tropical systems earlier this season.

Hazardous Conditions
Tropical Storm Cempaka will likely bring heavy rainfall, strong winds, and storm surge across the affected area through at least July 24. Impacts will likely be felt across parts of Guangdong, southeastern Guangxi, and Hainan. Forecast models indicate up to 20 cm (8 inches) of additional rainfall are possible per day in parts of western Guangdong. Severe weather impacts are possible in coastal areas of eastern Guangdong, Fujian, and southern Taiwan from July 25-26, depending on the system's track and intensity.

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 heavy rain, flooding, and storm surge, the system could produce damaging wind gusts in affected regions. Tropical-storm-force wind gusts may occur. Localized power outages are possible due to uprooted trees and toppled utility lines.

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 24. 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 weather 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 and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events.

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.

Resources

China Meteorological Administration
Joint Typhoon Warning Center