Typhoon Ampil: Strongest Tokyo Threat Since 2019 Disrupts Eastern Japan
Typhoon Ampil in 2024 became the strongest storm to threaten the Tokyo region since Typhoon Faxai in 2019 as it approached eastern Japan. The storm reached peak intensity on August 16 with a central pressure of 950 hPa and maximum sustained winds of 85 knots, equivalent to a Category 4 hurricane on the Saffir-Simpson scale based on JTWC standards, with 1-minute sustained winds reaching approximately 215 km/h (130 mph). Ampil remained offshore but brought powerful winds, heavy rainfall, flight cancellations, railway suspensions, and power outages across parts of eastern Japan. The system became an extratropical cyclone at 00:00 UTC on August 19 and its remnants moved across the North Pacific toward the Bering Sea and Aleutian region before dissipating on August 23.
From Tropical Depression to Very Strong Typhoon: Ampil’s Rapid Intensification over the Kuroshio
Ampil originated as a tropical depression over the western Pacific south of Japan at 12:00 UTC on August 11, 2024. The system developed in an environment influenced by warm ocean temperatures along the western Pacific, allowing its circulation to organize rapidly as it moved northeastward toward Japan.
At 12:00 UTC on August 12, Ampil strengthened into a tropical storm, with its central pressure falling to 998 hPa. By August 13 and 14, the system intensified significantly, reaching a central pressure of 975 hPa and maximum sustained winds of 60 knots as its inner circulation became better defined.
On August 15, Ampil reached typhoon intensity while moving over waters east of Japan. The system continued strengthening over the Kuroshio region, where warm sea surface temperatures supported further development. By August 16, the typhoon reached its maximum strength near 36.2°N, 143.3°E.
At peak intensity, Ampil had a minimum central pressure of 950 hPa and maximum sustained winds of 85 knots (10-minute sustained winds under the Japan Meteorological Agency standard). The Japan Meteorological Agency classified Ampil as a “very strong” typhoon, while the Joint Typhoon Warning Center assessed the system as a Category 4-equivalent storm based on 1-minute sustained winds of approximately 215 km/h (130 mph).
For mainland China, Taiwan, Hong Kong, and Macao, Ampil did not move into nearby coastal waters and caused no direct land impacts. Regional attention focused mainly on Japan’s Pacific coast, aviation routes, and marine operations across the western Pacific.
950 hPa Core: Ampil’s Offshore Passage Triggers Tokyo Region Travel Chaos
Ampil reached its peak strength on August 16 while remaining offshore east of Japan. The typhoon’s center passed over the Pacific east of the Kanto region, with its powerful wind field extending toward Tokyo, Chiba, Kanagawa, and Fukushima coastal areas.
Japan’s Meteorological Agency issued warnings for strong winds, high waves, heavy rain, flooding risks, and possible landslides. Local governments including areas near Tokyo and northeastern coastal prefectures issued evacuation advisories for residents in vulnerable locations and opened designated shelters.
The storm caused major disruptions during Japan’s peak summer travel period. Haneda Airport and Narita Airport cancelled a combined 1,284 flights, including 935 cancellations at Haneda and 349 at Narita, as airlines adjusted operations due to worsening weather conditions. Railway operators also suspended services, including the full Tokyo–Nagoya section of the Tokaido Shinkansen, causing widespread delays for passengers.
Strong winds associated with Ampil damaged power infrastructure in parts of eastern Japan. Approximately 2,000 households temporarily lost electricity as utility crews worked to restore service.
Although Ampil did not make landfall, its offshore passage produced significant impacts across the Tokyo metropolitan region. The combination of a powerful wind field, high population density, and disrupted transportation networks made it one of the most closely monitored typhoon events affecting eastern Japan in recent years.
Hundreds of Flights Cancelled: Ampil’s Outer Bands Disrupt Tokyo Transportation Network
Around August 16, Ampil’s outer rainbands spread across eastern Japan, bringing periods of heavy rainfall and strong winds. Coastal areas experienced rough seas, while inland locations monitored risks from flooding and slope failures.
Municipal authorities across affected areas increased emergency response measures. Residents in low-lying zones and locations with elevated landslide risks received evacuation guidance, while local governments maintained public alerts through official communication channels.
Transportation remained the most visible impact sector. Airlines cancelled more than one thousand flights at major Tokyo airports, affecting domestic and international passengers. Railway operators adjusted schedules according to wind conditions, with high-speed rail services and regional trains experiencing cancellations and delays.
Public facilities and outdoor events across parts of the Kanto region were also affected. Local authorities restricted some outdoor activities and adjusted operations at facilities exposed to severe weather conditions while monitoring storm developments.
For China, Taiwan, Hong Kong, and Macao, Ampil remained a monitored western Pacific system rather than a direct disaster threat. Its movement demonstrated the wider regional influence of strong offshore typhoons on East Asian transportation and weather patterns.
From Typhoon to Extratropical Low: Ampil’s 3,000-Kilometer Final Pacific Journey
After passing east of Japan, Ampil began weakening as it moved northeastward into higher latitudes. The storm’s central pressure increased and its tropical structure gradually deteriorated under changing atmospheric conditions.
At 00:00 UTC on August 19, Ampil completed its transition into an extratropical cyclone near 44.3°N, 162.7°E. The system then continued its northeastward movement across the North Pacific, passing toward the Bering Sea and the Aleutian region as it lost its tropical characteristics.
The former typhoon continued through colder waters and higher-latitude environments before dissipating on August 23. During its final stage, Ampil’s remnants completed a Pacific journey of roughly 3,000 kilometers from the waters east of Japan toward the northern Pacific.