Philippine Sea: Typhoon In-Fa tracking northwestward in the Philippine Sea late July 22 /update 5

Event

Typhoon In-Fa is tracking northwestward in the far northern reaches of the Philippine Sea late July 22. As of 21:00 JST, the system's center of circulation was approximately 333 km (207 miles) south-southwest of Okinawa, Japan. Forecast models indicate the system will strengthen slightly and shift to the north-northwest as it makes a close approach to Japan's Yaeyama Islands on July 23. The system will then weaken as it tracks northwestward across the East China Sea and passes northeast of Taiwan. In-Fa is forecast to make landfall as a tropical storm north of Taizhou, Zhejiang Province, in mainland China on July 25. Following landfall, In-Fa is likely to weaken rapidly and shift to the west, then southwest, over Zhejiang Province before dissipating. Some uncertainty remains in the track and intensity forecast, and minor changes could occur in the coming days.

Government Advisories
As of late July 22, the Japan Meteorological Administration has issued purple warnings (the highest level on a three-tier scale) for storm surge for Ishigaki 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 23.

The Taiwan-based Central Weather Bureau has issued Extremely Heavy Rain advisories (the third-highest level on a four-tier scale) for parts of Hsinchu, Miaoli, and Yilan counties as well as Taipei, New Taipei, and Taoyuan cities through at least late July 23.

The China Meteorological Administration has issued a typhoon warning for strong winds for the southern Jiangsu coast, Zhejiang coast, and central and northern Fujian, as well as heavy rain warnings for the coast of central and northern Zhejiang and most of Taiwan Island. Approximately 10-16 cm (4-6 inches) of rain is possible in the affected areas.

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 Typhoon In-Fa cannot be discounted if weather conditions prove particularly hazardous.

Hazardous Conditions
Typhoon In-Fa will bring heavy rainfall, strong winds, and storm surge across the affected area through at least July 27. 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, Typhoon 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 27. 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
Philippine Atmospheric, Geophysical and Astronomical Services Administration