More rain to target Japan through Sunday morning, raising the risk for flooding

Several rounds of rain will target eastern Asia through the weekend, raising the risk for flooding and some snow.

Periods of rain and thunderstorms first drenched parts of China through the middle of the week as a storm system organized over the country. The storm slowly shifted into the East China Sea.

The heaviest rain fell across South Korea on Thursday and Thursday night. The highest rainfall total was on the island of Jeju, south of the Korean Peninsula, where the city of Seogwipo recorded 85 mm (3.3 inches). Into the weekend, Jeju and the rest of southern South Korea will have occasional showers.

The threat for heaviest rain has shifted into Japan, including Honshu and the city of Tokyo, through Sunday morning.

Tropical moisture surging northward will bring the heaviest rain to Kyushu, Shikoku and western Honshu. Kyushu is expected to receive the heaviest rain with 150 mm (6 inches) forecast in some locations, according to AccuWeather Senior Meteorologist Adam Douty.

As of Friday evening, local time, southwestern Japan had been hit the hardest. On the western side of Kyushu, the city of Hirado recorded 134 mm (5.3 inches), while 109 mm (4.3 inches) fell on Fukue Island.

Cities such as Hiroshima and Nagasaki reported around 64 mm (2.5 inches) as of Friday evening.

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"With yet another round of rain on the way this weekend, many places are likely to total 50-75 (2-3 inches) of rain in the span of just a few days," said AccuWeather Meteorologist Courtney Travis.

Even lesser-hit areas in Japan could end up with at least 25 mm (1 inch).

"Flash flooding will be a concern for any areas hit by downpours several times. Ponding in low-lying and poor drainage areas could occur with almost any downpour," Travis added.

The risk for mudslides in rugged terrain will also increase as the second round of rainfall falls through Sunday morning.

A man with a protective mask stands in the rain near an electronic stock board at a securities firm in Tokyo Monday, March 23, 2020. Shares dropped in Hong Kong and South Korea early Monday. However, Japan's Nikkei 225 index held steady, gaining 0.8% on news the International Olympic Committee plans to discuss potentially changing the timing of the Tokyo Games, due to begin in July. (AP Photo/Eugene Hoshiko). The IOC since postponed the Tokyo Games to 2021.

"The storm will pull cooler air behind it, bringing in the chill that has settled over northeastern China. This will allow precipitation late Saturday night into Sunday morning across central Honshu to end as snow, especially in the higher elevations," added Travis.

Tokyo is likely to miss out on the wintry weather, although a few flakes are not out of the question for northwestern parts of the city.

Other than along the southeast coast, mostly dry conditions will return to most of Japan on Sunday as the storm system departs to the east. Meanwhile, yet another storm looks to bring more rain to eastern China.

The rain in eastern China on Sunday is likely to bring yet another round of unsettled weather to portions of Japan before the middle of the week.

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