Philippine Sea: Typhoon Koinu tracking northwestward east of Taiwan as of early Oct. 4 /update 2

Event

Typhoon Koinu (known in the Philippines as Jenny) is tracking northwestward in the Philippine Sea early Oct. 4. As of 05:00 CST, the system's center of circulation is approximately 450 km (131 miles) southeast of Taipei, Taiwan.

Forecast models indicate that the storm will weaken slightly as it tracks westward across the Philippine Sea and make landfall as a typhoon over far southern Taiwan early Oct. 5. Koinu is forecast to weaken further into a tropical storm as it continues westward across the Taiwan Strait towards Guangdong Province, China, through Oct. 7 before making a close approach to the province early Oct. 8-9. Uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

As of early Oct. 4, the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) has issued Tropical Cyclone Wind Signal (TCWS) 3 across northern Batanes Province, TCWS 2 over the rest of Batanes Province and northern Babuyan Islands, and TCWS 1 across the rest of Babuyan Islands as well as northern mainland Cagayan, northern Apayao, and northern Ilocos Norte provinces. Rainfall of up to 20 cm (8 inches) is forecast over Batanes and up to 10 cm (4 inches) over the northern Babuyan Islands Oct. 4.

Taiwan's Central Weather Bureau has issued strong wind advisories over southern, eastern, and western Taiwan. Orange extremely heavy rain advisories (second-lowest level on a four-tier scale) are in place over Hualien, Pingtung, Taitung, and Yilan counties and New Taipei City, while yellow heavy rain advisories are in effect for most of the rest of northern Taiwan.

The Japan Meteorological Agency (JMA) has issued red (middle level on a three-tier scale) high wave warnings over Ishigaki, Miyako, and Yonaguni islands and yellow thunderstorm and gale advisories across most of the Ryukyu Islands. Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days.

Authorities in Philippines have suspended general aviation or non-commercial flights at Basco Airport (BSO) as of the evening of Oct. 3. Classes were suspended in parts of Pangasinan Municipality Oct. 3. Airlines in Taiwan have canceled international flights connecting Kaohsiung with Nagoya, Narita, and Osaka in Japan, Hong Kong, and Gimpo in South Korea Oct. 4-5, and canceled multiple domestic flights over the same period. Officials have canceled 96 ferries on 12 routes connecting southern Taiwan. All schools and offices in Penghu County and Orchid Island and Green Island in Taitung County are closed Oct. 4, as well as in Hengchun, Manjhou, Checheng, Fangshan, Mudan, and Sisigu townships in Pingtung County and the rest of Taitung County from the afternoon of Oct. 4.

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

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. 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 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 (JTWC)
Japan Meteorological Agency (JMA)
Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA)
Taiwan Central Weather Bureau
China Meteorological Administration