Three Typhoons Simultaneously South of Japan — Typhoon No. 18 at 950hPa with Maximum Winds of 45m/s to Approach the Daito Islands on the 25th

Explanation

As of 15:00 on August 23, three typhoons exist simultaneously from south of Japan to the East China Sea. Typhoons No. 18, No. 19, and No. 20 vary in both strength and direction of movement. Having three typhoons at once is not itself unusual, but the clear difference in intensity among them is a distinctive feature this time.

The strongest is Typhoon No. 18 (international name Saudel). According to Weathernews, as of 15:00 on the 23rd, it was located near the Ogasawara Islands (21°55'N, 141°5'E), with a central pressure of 950hPa and maximum wind speed near the center of 45m/s. At the pre-dawn observation (3:00) on the same day, the central pressure was 950hPa and maximum wind speed was 40m/s, so the winds strengthened during the day. Maintaining its strong intensity, it is expected to approach the Daito Islands of Okinawa Prefecture on the 25th.

When expressing the strength of a typhoon, a smaller pressure value means a stronger storm. Since the average surface-level pressure is about 1013hPa, a value of 950hPa means the air near the center is that much thinner, causing winds blowing in from the surroundings to become faster.

Typhoon No. 19 (Nara) is in the Gulf of Tonkin, with a central pressure of 994hPa and maximum wind speed of 18m/s. It is expected to barely move and to weaken into a tropical depression by midweek, with no direct impact on Japan. Typhoon No. 20 (Kenari) was in the Taiwan Strait (25°20'N, 120°55'E) at 15:00 on the 23rd, with a central pressure of 998hPa and maximum wind speed of 18m/s, moving west at 10km/h. It is expected to weaken into a tropical depression in the Taiwan Strait by 15:00 on the 24th.

Of these, Typhoon No. 20 was the closest to Japan on the 23rd. According to an article by Japan Weather Association forecaster Yoshiyuki Maki, as of 3:00 on the 23rd, Typhoon No. 20 was located about 100km north of Yonaguni Island, and it was reported that a linear precipitation band could develop in the Yaeyama region toward the evening. The forecast hourly rainfall was 60mm for Ishigaki Island and 80mm for Yonaguni Island. Over the 24 hours until 6:00 on the 24th, 150mm was expected for Ishigaki Island and 180mm for Yonaguni Island.

A linear precipitation band refers to a state in which developed cumulonimbus clouds form one after another in a line, continuing to produce rain over the same area for hours. An ordinary cumulonimbus cloud dissipates within several tens of minutes, but when new clouds keep forming upwind, the line of clouds stays in place while rain continues to be supplied. This is why heavy rain can occur even far from the center of a typhoon. Judging only by the typhoon's position and concluding "it's still far away, so it's fine" is not reliable, because it is the inflow of moist air, not the center, that produces the rain.

Source: Japan Weather Association tenki.jp, "Risk of a linear precipitation band today, the 23rd, due to Typhoon No. 20; Typhoon No. 18 to directly hit Okinawa on the 26th" https://tenki.jp/forecaster/y_maki/2026/08/23/40260.html / Weathernews Typhoon Information https://weathernews.jp/onebox/typhoon/ / tenki.jp Typhoon No. 20 (2026) https://tenki.jp/bousai/typhoon/2620/