East China Sea: Tropical Storm In-Fa tracking north-northwestward in the East China Sea early July 24 /update 8

Event

Tropical Storm In-Fa is tracking north-northwestward across the East China Sea early July 24. As of 06:00 JST, the system's center of circulation was approximately 315 km (195 miles) west-southwest of Kadena Air Base, Japan. Forecast models indicate the system will strengthen briefly into a typhoon during its passage across the East China Sea through early July 25, before it weakens to a tropical storm again and turns northwestward toward Zhejiang Province, mainland China. In-Fa is forecast to make landfall over Xiangshan County south of Ningbo late July 25. Following landfall, the storm will rapidly weaken as it continues west across Zhejiang Province, potentially dissipating near the border of Zhejiang and Jiangxi provinces by late July 28. Some uncertainty remains in the track and intensity forecast, and minor changes could occur in the coming days.

Government Advisories
As of early July 24, the Japan Meteorological Administration has issued purple warnings (the highest level on a three-tier scale) for storm surge for Kume Island in Okinawa Prefecture. Red warnings (the second-highest level on a three-tier scale) for storms and high waves are also in place for Amami Islands, Kagoshima Prefecture, as well as the rest of Okinawa Prefecture through at least July 24.

The Taiwan-based Central Weather Bureau has maintained Torrential Rain advisories (the second-highest level on a four-tier scale) for parts of Taoyuan City and Hsinchu County. Extremely Heavy Rain advisories are in effect for Miaoli and Yilan counties as well as Keelung, Taipei, and New Taipei cities through at least late July 25.

The China Meteorological Administration has issued a typhoon warning for strong winds for coastal areas in central and northern Fujian, central and southern Jiangsu, and Zhejiang provinces and Shanghai. Heavy rain warnings are in effect for the northern and eastern Zhejiang Province and Shanghai, with extremely high rainfall totals of up to 20cm (8 inches) forecast in parts of eastern Zhejiang Province July 24-25.

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. The possibility of localized evacuations due to Tropical Storm In-Fa cannot be discounted if weather conditions prove particularly hazardous.

Hazardous Conditions
Tropical Storm In-Fa will bring heavy rainfall, strong winds, and storm surge across the affected area through at least July 28. 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, Tropical Storm In-Fa could produce damaging wind gusts in areas along its forecast track. 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 28. 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.

Health
Stagnant pools of water during and after flooding increase the incidence of insect- and waterborne diseases, such as dengue fever, cholera, and malaria. The threat of these disease outbreaks is usually elevated in low-income or underdeveloped areas of major urban centers due to incomplete or open sewer lines. The latent threat of waterborne contaminants from inundated industrial sites cannot be discounted; 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 all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high 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
Japan Meteorological Agency
Central Weather Bureau
China Meteorological Administration