The Japan Meteorological Agency issued a half-day ahead forecast for line-shaped rain bands over Kochi Prefecture as Typhoon No. 6 moves northward [1, 2].
These warnings are critical because line-shaped rain bands can cause sudden, intense rainfall leading to flash flooding and landslides. The agency also issued coastal wind-and-wave warnings, noting that the risk of heavy-rain disasters could rise sharply [1, 2].
The storm is currently moving northward past the Kagoshima area [1, 2]. In Kochi City, the impact was felt early Tuesday at the coastal area of Katsurahama. A reporter for TBS NEWS DIG said, "The wind suddenly became stronger after 9:30 a.m." [1].
Rainfall measurements at Katsurahama reached 65.0 mm by 5 p.m. [1]. The agency's forecast for the next 24 hours suggests significant accumulation across the region. Eastern Kochi is expected to see 250 mm of rainfall [1], while central and western Kochi are forecast to receive 200 mm [1].
Other regions have already experienced extreme weather. In parts of Miyazaki Prefecture, total rainfall has already exceeded 300 mm [3].
Local authorities are monitoring the situation as the typhoon continues its trajectory. The current forecast covers the window up to noon Wednesday [1, 2].
“The risk of heavy-rain disasters could rise sharply.”
The use of a half-day ahead forecast for line-shaped rain bands represents an effort by Japanese meteorologists to provide earlier warnings for localized, high-intensity precipitation. Because these weather patterns are volatile and can trigger rapid flooding, the extended lead time is intended to allow residents in vulnerable coastal and mountainous areas of Kochi and Miyazaki to evacuate or secure property before the most dangerous rain begins.
