A stalled frontal boundary from southeastern China through Taiwan and Japan will be the focal point for rounds of heavy rainfall into early next week.
While the entire region will not receive heavy rainfall each day, on any given day rainfall of 25-50 mm (1-2 inches) will be possible with total rainfall through early next week averaging 75-150 mm (3-6 inches).
The hardest-hit areas will receive more than 300 mm (12 inches) of rain. This amount of rainfall is most likely in western Taiwan and Kyushu, Japan.
While flash flooding will be the biggest concern, days of heavy rainfall over the same areas can also lead to river flooding.
In Hong Kong, downpours are possible each day through early next week; however, the greatest threat for flooding appears to be Saturday through Monday.
Areas from Guizhou and Guangxi provinces through Jiangxi and Fujian provinces will also be battered with rounds of heavy rainfall into early next week which will total 75-150 mm (3-6 inches) leading to a high risk for flooding.
Along this stalled frontal boundary, several areas of low pressure will track from southwest to northeast enhancing rainfall and potentially aiding in the development of a tropical system in either the South China Sea or the East China Sea.
Regardless of if any tropical system develops, rounds of heavy rainfall will target Hong Kong, Taipei, Tokyo and surroundings areas from the rest of the week and into early next week.
If tropical develop were to occur near this stationary boundary, a northeast track would be expected which would bring the worst impacts to Japan; however, any tropical system would likely remain much weaker than the previous cyclones that have moved this region.