Japan: Storm Lupit weakens to extratropical cyclone as it tracks northeastward across Sea of Japan late Aug. 9 /update 11

Event

Tropical Storm Lupit is tracking northeastward across the Sea of Japan late Aug. 9. As of 18:00 JST, the storm's center of circulation was approximately 65 km (40 miles) north of Nigata, Nigata Prefecture, Japan. The system has now weakened to an extratropical cyclone, though forecast models indicate it will track further northeastward, making another landfall near Sakata, Yamagata Prefecture, late Aug. 9 or early Aug. 10. The system is subsequently projected to track across Tohoku Region's Yamagata, Akita, and Iwate prefectures and then exit into the North Pacific Ocean by early Aug. 10. Some uncertainty remains in the system's track and intensity forecast, and changes may occur over the coming days.

As of Aug. 9, evacuation orders were previously issued for more than 300,000 people across Hiroshima, Shimane, Ehime, Fukuoka, and Kagoshima prefectures. Dozens of flights have been canceled from airports in affected prefectures of Kyushu and southwestern Honshu. More flights could be canceled if conditions worsen.

Government Advisories

As of 18:00 Aug. 9, the Japan Meteorological Agency had issued the following alerts, warnings, and advisories:

• Purple (i.e., the highest level on a three-tier scale) alerts for landslides are in effect for parts of Shimane prefecture.

• Various orange (i.e., second-highest level on a three-tier scale) warnings, including for heavy rain, landslides, flooding, storm gales, and high waves, are in effect for parts of Tokyo, Kyoto, Tottori, Kanagawa, Mie, Aichi, Chiba, Shizuoka, Fukushima, Gifu, Hyogo, Ishikawa, Iwate, Miyagi, Oshima, Wakayama, Shimane, Hiroshima, Yamaguchi, Fuiki, Toyama, and Oita prefectures.

• Yellow (i.e., lowest level on a three-tier scale) advisories for heavy rain, landslides, flooding, high waves, storm gales, storm surge, and thunderstorms are in effect for much of the rest of the affected areas.

By early Aug. 10, heavy rainfall is likely to affect much of Japan, with rainfall totals of up to 30 cm (12 inches) forecast for Tokai Region, 18 cm (7 inches) for Kanto and Koshin regions, 15 cm (6 inches) for Hokuriku Region, 12 cm (5 inches) for Hokkaido and Shikoku regions, and 10 cm (4 inches) for Tohoku Region. Locally higher rainfall totals are possible through early Aug. 10, and additional rainfall forecast through early Aug. 11 may further increase chances for flooding in low-lying communities.

Authorities could issue new warnings or update existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards. The possibility of additional localized evacuations cannot be discounted if weather conditions prove particularly hazardous.

Hazardous Conditions

The storm could bring heavy rainfall, strong winds, and rough seas to much of Japan and parts of southeastern South Korea and far southeastern Russia over the coming days. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed or a lack of 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. Persistent onshore flow could make it difficult for the surge to recede and for water levels to decrease in coastal river catchments.

Transport

In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger further localized business, transport, and utility disruptions. Floodwaters and debris flows could render some bridges or roadways impassable, impacting overland travel, including rail services, 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 further 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 major urban centers' low-income or underdeveloped areas 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 adverse weather 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 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 (JTWC)
Japan Meteorological Agency