The Japan Meteorological Association has announced information regarding the forecast for heavy rain and disasters associated with Typhoon No. 10 (as of August 26 at 12:00) in the disaster prevention report (First Report).
Key Points
・The strong Typhoon No. 10 is expected to approach western Japan from August 29 and may traverse through western and eastern Japan.
・The speed of the typhoon’s movement is slow, and there is a risk of record rainfall, particularly along the Pacific coast of western to eastern Japan. There is a need for severe vigilance against river flooding and landslides over a wide area.
・In Miyazaki Prefecture, rainfall over 48 hours may exceed 600 mm by the 29th, potentially surpassing 150% of the previously highest recorded precipitation. After that, there is also a possibility of heavy rain in southern Shikoku, southern Kinki, and the Tokai region until the 31st.
As of August 26 (Monday) at 12:00, Typhoon No. 10 is located over the sea south of Japan, moving northwest at a speed of about 20 km/h. The central pressure is 980 hPa, and the maximum wind speed near the center is 35 m/s. After this, the typhoon is expected to approach western Japan and may traverse through western and eastern Japan after the 29th.
According to the Japan Meteorological Association’s exclusive “JWA Integrated Weather Forecast” (*1), the rainfall over 48 hours from 00:00 on the 28th (Wednesday) to 24:00 on the 29th (Thursday) is predicted to exceed 600 mm in parts of Kyushu. If the expected rainfall occurs, the ratio compared to the maximum recorded rainfall observed to date (previous maximum ratio *2) may exceed 150% (Figure 1). A joint study result by the Japan Meteorological Association and Professor Motokata Ushiyama of Shizuoka University (*3) indicates that when the previous maximum ratio reaches 100%, casualties begin to occur, and if it exceeds 150%, the number of casualties may increase sharply, making it imperative to exercise severe vigilance due to the extremely high risk of disaster occurrence.
Warm, moist air associated with the typhoon is expected to flow into the Pacific coast of western to eastern Japan, with rain continuing from the 28th (Wednesday) (Figure 2). Due to prolonged heavy rain, there is a need for severe vigilance against river flooding and landslides. Heavy rain is predicted for the Kyushu region from the 28th (Wednesday) to the 29th (Thursday) and from the 29th (Thursday) to the 31st (Saturday) in the Shikoku and Tokai regions.
A characteristic of this typhoon is its slow moving speed. Therefore, it is expected that the area will receive prolonged rain in the same locations. If the typhoon follows a course that traverses from western Japan to eastern Japan, even in regions like eastern Kyushu, southern Shikoku, southern Kinki, and the Tokai region, where rainfall is usually high, there is a risk of record-breaking rainfall that exceeds previously recorded maximums. Vigilance is necessary for the occurrence of flooding in many rivers, including large rivers, and widespread landslides primarily along the Pacific coast from western to eastern Japan. Please make early preparations and act before the rainfall intensifies.
Note that there is still a range in the forecasted path of the typhoon. Depending on the path of the typhoon, the rainfall predictions may change significantly, so please check the latest weather information.
This information was created based on forecast materials as of 12:00 on August 26, 2024. Please confirm the latest weather information.
*1 JWA Integrated Weather Forecast: https://www.jwa.or.jp/news/2023/02/19157/
*2 Previous Maximum Ratio: The ratio compared to the maximum value of observed rainfall since May 2006, which has been analyzed and converted to a 1 km mesh.
*3 Motohiro Honma, Motokata Ushiyama: Research on estimation methods for the number of casualties in heavy rain disasters, Natural Disaster Science, Vol. 40, Special Issue, pp. 157-174, 2021.
*The official weather forecast media of the Japan Meteorological Association “tenki.jp” (https://tenki.jp/) provides disaster prevention information such as “Warnings and Advisories,” “Earthquake Information,” “Tsunami Information,” “Volcano Information,” and “Typhoon Information” 24 hours a day, 365 days a year.
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PDF Download: 【Japan Meteorological Association_Disaster Prevention Report 2024-Vol.4】Forecast for Heavy Rain Associated with Typhoon No. 10 (First Report) _