East China Sea: Typhoon Hinnamnor tracking north-northwestward in East China Sea early Sept. 4 /update 7

Event

Typhoon Hinnamnor is tracking north-northwestward over the East China Sea early Sept. 4. As of 03:00 JST, the system's center of circulation was located near Japan's Yaeyama Islands, approximately 355 km (220 miles) west-southwest of Kadena Airbase, Okinawa Prefecture, Japan.

Forecast models indicate that the storm will strengthen as it moves further northward into the East China Sea and away from the Yaeyama Islands through early Sept. 5. The system is subsequently forecast to turn northeastward and weaken while maintaining typhoon-force winds as it makes a close approach to South Korea's Jeju Province and landfall in South Gyeongsang Province Sept. 6. After traversing southeastern South Korea, Hinnamnor is forecast to exit into the Sea of Japan and transition into a post-tropical cyclone with typhoon-force winds by early Sept. 7, passing near Russia's Primorsky Krai. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

The Japan Meteorological Agency (JMA) has warned of strong winds, rough seas, heavy rainfall, and thunderstorms over parts of Okinawa Prefecture through at least Sept. 4. Waves of around 10 meters (23 feet) in height are forecast in the Okinawa region and around 7 meters (23 feet) in the Amami region Sept. 4. Storm surge is possible in parts of Okinawa Prefecture through Sept. 4. Through 06:00 Sept. 5, 20 cm (8 inches) of rainfall are forecast in Okinawa region and southern Kyushu, 15 cm (6 inches) in Amami region and Shikoku, 12 cm (5 inches) in northern Kyushu, and 10 cm (4 inches) in Tokai region. Heavy rainfall associated with the storm system and other meteorological disturbances is also forecast across much of western and southern Japan into at least early Sept. 7.

As of early Sept. 4, the JMA has issued purple heavy rainfall and landslide warnings (the highest level on a three-tier scale) across northern Okinawa Island and northern parts of Kyushu's Miyazaki Prefecture. Red storm warnings and high wave warnings (the second-highest level on a three-tier scale) are in place across most of Okinawa Prefecture. The JMA has also issued a red high wave warning for Amami region. Further weather warnings with a varying degree of association with the storm system have been issued across parts of the rest of Japan.

Taiwan's Central Weather Bureau has notably issued a sea and land typhoon warning for the storm. Authorities have also issued a red torrential rain advisory (the second-highest level on a four-tier scale) for Hsinchu County, as well as orange extremely heavy rain advisories (the third-highest level on a four-tier scale) for Keelung, Taipei, New Taipei, Taoyuan, and Kaohsiung cities as well as Miaoli, Nantou, Yunlin, Chiayi, and Yilan counties. Yellow heavy rain advisories (the lowest level on a four-tier scale) are in place across much of the rest of northern and northwestern Taiwan.

The China Meteorological Administration has issued a yellow-level typhoon warning (the second-lowest level on a four-tier scale); heavy rainfall is forecast across northeastern Zhejiang Province, southern Liaoning Province, and southern Jilin Province, while strong winds are likely in the East China Sea and surrounding coastal waters.

While the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has lifted tropical cyclone wind signals in connection with the storm, it has nonetheless warned of heavy rainfall that is forecast to affect parts of northern and central Luzon into early Sept. 5.

Officials will likely update and extend the coverage of the relevant weather alerts over the coming days as the system progresses.

Japan Airlines (JL) has warned that irregular flight operations, including the partial or total cancellation of scheduled flights, are possible at Kikai (KKX), Amami (ASJ), Tokunoshima (TKN), Okinoerabu (OKE), Yoron (RNJ), Kumejima (UEO), Naha (OKA), Miyako (MMY), Tarama (TRA), Ishigaki (ISG), and Yonaguni (OGN) airports Sept. 4.

All Nippon Airways (NH) has also warned that flight disruptions, including delays, cancellations, and diversions, are possible at Goto-Fukue (FUJ), OKA, MMY, and ISG through Sept. 4. Further flight disruptions are likely to affect Japanese carriers as the storm progresses.

Authorities have issued evacuation orders for portions of Okinawa and Niigata prefectures due to the typhoon and associated severe weather. As of late Sept. 3, around 2,920 households in Okinawa Prefectures's Miyakojima City, 330 households in Tarama Village, 190 households in Ishigaki City, and 10 households in Taketomi Town were without power.

Hinnamnor has also triggered ferry and flight disruptions in Taiwan in recent days. Further ferry and flight disruptions are possible in Taiwan over the coming hours as the storm tracks northward.

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

The inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Raw sewage and other hazardous materials mixed with floodwaters pose a serious health threat.

Advice

Activate contingency plans in areas where officials forecast typhoon or 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
Japan Meteorological Agency
Taiwan Central Weather Bureau
China Meteorological Administration
Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)
Korea Meteorological Administration