Philippine Sea: Typhoon Hinnamnor tracking northwestward in the Philippine Sea late Sept. 2 /update 5

Event

Typhoon Hinnamnor is tracking northwestward over the Philippine Sea late Sept. 2. As of 21:00 JST, the system's center of circulation was approximately 567 km (352 miles) south-southwest of Kadena Airbase, Okinawa Prefecture, Japan.

Forecast models indicate that the storm is expected to strengthen slightly as it tracks generally northward Sept. 3 before making landfall over the Yaeyama Islands late Sept. 3. After landfall, Hinnamnor is initially forecast to strengthen as it continues to track northward then north-northeastward in the East China Sea Sept. 4, before weakening as it turns to track northeastward as it passes eastern mainland China Sept. 5. The storm is expected to weaken further as it continues to track northeastward towards the Korean Straight, making a close approach to Jeju Island, South Korea, late Sept. 5 before making landfall over the southwestern coast of South Gyeongsang Province early Sept. 6. The system is forecast to weaken to an extratropical cyclone as it tracks northeastward across the southwestern tip of the Korean Peninsula Sept. 6 before exiting into the Sea of Japan off the southern coast of North Gyeongsang Province. 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. Maximum wind speeds of around 180 kph (112 mph) and gusts up to 252 kph (157 mph) are expected in the region Sept. 3 and around 144-180 kph (89-112 mph) with gusts of 198-252 kph (123-157 mph) Sept. 4. Waves of around 10 meters (23 feet) in height are expected in the Okinawa region Sept. 3-4 and around six meters (20 feet) in the Amami region Sept. 3 and eight meters (26 feet) Sept. 4. Storm surge is possible in parts of Okinawa Prefecture from late Sept. 2 through early Sept. 4. Rainfall amounts of around 15 cm (6 inches) are forecast in Okinawa Prefecture late Sept. 2-late Sept. 3 and around 20-30 cm (8-12 inches) late Sept. 3-late Sept. 4. Heavy rainfall associated with the storm system and other meteorological disturbances is also forecast across parts of western and eastern Japan through Sept. 4.

As of late Sept. 2, the JMA has issued red high wave warnings (the second highest level on a three-tier scale) and yellow storm surge, storm gale, and thunderstorm warnings across most of Okinawa Prefecture. Further weather warnings with a varying degree of association with the storm system have been issued across parts of the rest of Japan. Purple heavy rainfall and landslide warnings have been issued for Mie Prefecture and parts of Shiga Prefecture and red heavy rainfall and landslide warnings for Osaka, the rest of Shiga, and northern and western Yamaguchi prefectures, as well as Tsushima Island in Nagasaki Prefecture. Yellow heavy rainfall, landslide, flood, storm gale, high waves, storm surge, and thunderstorm warnings have been issued across much of western and parts of southeastern Japan.

Taiwan's Central Weather Bureau has issued a sea typhoon warning for the storm which may be upgraded to a land warning as the typhoon passes closer. Orange extremely heavy rain advisories (the second lowest level on a four-tier scale) have been issued for Hsinchu County, Keelung City, New Tapei City, Taoyuan City, mountainous areas of Tapei City, and mountainous areas of Yilan County. Yellow heavy rain advisories have been issued for Miaoli County, mountainous areas of Taichung City, lower elevation areas of Taipei City, and lower elevation areas of Yilan County.

The China Meteorological Administration has issued a yellow level typhoon warning (the second lowest level on a four-tier scale) as of Sept. 2. The administration has warned of heavy rainfall of around 5-11 cm (2-4 inches) in eastern Zhejiang Province late Sept. 2-late Sept. 3, as well as strong winds in the East China Sea and surrounding coastal waters.

The Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) has warned of heavy rainfall over Ilocos Norte, Batanes, Babuyan Islands, and Abra late Sept. 2 and Batanes Sept. 3. Light-to-moderate rainfall is forecast over Cagayan and the rest of Ilocos and Cordillera Administrative regions late Sept. 2 and the Babuyan Islands Sept. 3. Tropical Cyclone Wind Signal No. 2 (level 2 out of 5) for Batanes Province and TCWS No. 1 for the Babuyan Islands and the northeastern portion of mainland Cagayan.

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 canceled all flights at Yonaguni Airport (OGN) Sept. 2 and at Shimojishima Airport (SHI) Sept. 3, as well as some flights at Okinawa Naha (OKA), Miyako (MMY), Tarama (TRA), and New Ishigaki (ISG) airports Sept. 2 and Okinawa Naha (OKA), Yoron (RNJ), and Kumejima (UEO) airports Sept. 3. All Nippon Airways (NH) has also canceled some flights at New Ishigaki (ISG) Airport Sept. 2 and early Sept. 4 as well as all flights at Miyako (MMY) and New Ishigaki (ISG) airports Sept. 4. Further flight cancellations are likely as the storm progresses.

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
Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA)
Korea Meteorological Administration