Japan back on alert for drenching rain, mudslides less than a week after deadly flooding

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Following downpours that triggered deadly mudslides and flooding in portions of Japan last week, more heavy rainfall will stream across the country into Friday.

Kanoya recorded 472.5 mm (18.60 inches) in a single day and more than 600 mm (25 inches) over a three-day period during last week's flooding event.

A new slow-moving storm system is unleashing widespread heavy rainfall from south to north into Friday, renewing the risk for flooding and mudslides for millions of people.

Downpours ahead of the storm's arrival triggered an evacuation advisory for Mihara in Kochi Prefecture on Tuesday.

Kyushu, far southwest Honshu and southern Shikoku were drenched by downpours from Wednesday into Wednesday night with widespread rainfall of 50-100 mm (2-4 inches) reported.

Total rainfall through Thursday night of 50-100 mm (2-4 inches) will be common across southern and central Japan with an AccuWeather Local StormMax™ of 300 mm (12 inches).

This magnitude of rainfall can lead to life-threatening flash flooding and mudslides. Travel delays are also expected to be common across the region.

Radar image showing rainfall spreading across Japan on Thursday, local time.

The rain will continue to slowly track northward into Friday, reaching the Greater Tokyo Area late Thursday night into Friday.

Localized flooding is possible; however, significant delays to the morning commute on Friday are expected.

The storm will shift northward this weekend, bringing scattered showers with local downpours to northern Honshu and Hokkaido.

Another round of downpours may once again target Kyushu, Shikoku and eastern Honshu this weekend continuing the risk for flooding and mudslides.

The rainy season typically affects Japan from May through July; however, additional rounds of heavy rainfall are possible from August to October as tropical cyclones affect the country.

South Korea will also be affected by this storm system with downpours forecast for southern and eastern parts of the country from Wednesday into Thursday. Localized flooding and travel delays are possible during this time.