NAHA - Western and eastern Japan face a prolonged risk of heavy rain into next week as Typhoon No. 24, a tropical depression and the autumn rain front combine to bring increasingly unstable weather across a wide area, with the typhoon currently located over waters northwest of Okinawa's main island after weakening considerably and losing much of its clearly defined circulation.
Some rain clouds are affecting Okinawa, although many areas between the rain bands remain relatively clear.
The greater concern is the warm, moist air flowing north of the typhoon and feeding into the autumn rain front, helping strengthen rain clouds well away from the storm's center.
Typhoon No. 24 is expected to move south through the morning of September 6 before turning east during the day. From September 7, it is forecast to turn north and trace a looping path around Okinawa.
The system is then expected to move farther north on September 8 and weaken into a tropical depression near Kyushu and western Japan by 9 a.m. on September 9.
Because the cloud structure around the center is already fragmented, Okinawa is considered unlikely to experience prolonged torrential rain directly from the typhoon, although brief heavy showers are possible through September 6.
High waves remain a concern around the Nansei Islands, and people are being advised to avoid marine leisure activities.
Another tropical depression east of Typhoon No. 24 is expected to move quickly northward and play an important role in the developing weather pattern.
As the tropical depression moves north, the autumn rain front is also forecast to shift gradually northward and become more active, while additional moist air flows around the systems.
Rain clouds are expected to develop over western and eastern Japan from September 6 into September 7.
Many areas that are seeing relatively settled conditions on September 5 are forecast to experience increasing rain during the daytime on September 6, with particularly strong rain clouds expected to develop along the Pacific side of eastern Japan from the evening.
The main rain area is then forecast to shift toward Tohoku through September 7.
Rainfall generated by the tropical depression and autumn rain front could become substantial over the 48 hours covering September 6 and September 7.
The Kanto region is expected to receive some of the heaviest rain, with parts of the area forecast to exceed 200 millimeters.
Heavy rain is also expected along the Pacific side of Tohoku, where rainfall totals could reach 150 to 200 millimeters, with some locations exceeding 200 millimeters.
Authorities are warning of an increased risk of landslides, rising rivers and flooding along smaller rivers and streams as the ground becomes saturated.
Rainfall is also expected to increase across Kinki and Shikoku from September 6 into September 7.
While the heaviest rain has recently been concentrated in southern Kyushu, the focus is expected to shift farther east from September 6.
The unsettled weather is likely to persist beyond the weekend because the autumn rain front is forecast to remain near Honshu through the latter half of next week.
Around September 8, rain is expected to spread again across western Japan as the remnants of Typhoon No. 24 approach as a tropical depression.
Widespread rain is also forecast on September 9 under the influence of the former typhoon, while the autumn rain front could continue producing intense rain across parts of western and eastern Japan.
The effects of Typhoon No. 24, the tropical depression and the autumn rain front could therefore continue for about a week, raising the risk of accumulating rainfall and weather-related disasters over a prolonged period.
Residents are being urged to continue monitoring the latest forecasts and remain alert for flooding, landslides and swollen rivers as repeated periods of heavy rain affect western and eastern Japan.
Previously: Typhoon No. 24 Loops South of Japan
Source: ウェザーニュース
