Tropical Storm Etau to Bring Flooding Rains to Japan, Kilo to Bypass

By Eric Leister, Meteorologist

September 7,2015; 9:10PM,EDT

 

 

While Typhoon Kilo will narrowly miss Japan, newly formed Tropical Storm Etau will bring flooding rain to the country this week.
Kilo, formerly a hurricane in the eastern and central Pacific Ocean, will continue to track to the west and northwest during the course of the week, eventually nearing Japan. While tracking across the western Pacific this week, Kilo is expected to remaining a powerful typhoon while at sea due to the combination of light wind shear and warm ocean water.
Ultimately, Kilo is expected to curve to the east of Japan from Friday into this weekend, not bringing significant impacts, though some outer rain bands could graze eastern Hokkaido.
Meanwhile, Tropical Storm 18W (Etau) has formed south of Japan and will become better organized in the next few days.
Etau will track generally northward bringing the new tropical system near Japan by midweek; however, moisture from Etau is already being pulled northward into Japan.

As tropical moisture flows to the north into Japan, rounds of heavy rain will fall from Monday night through at least Thursday. Lighter rain will linger through the rest of the week though the threat for flooding will have ended.
A zone across central and southern Honshu is expected to see the heaviest rainfall and greatest flooding threat. Tokyo, Nagoya, Hamamatsu and Shizuoka are all included in this zone of highest risk. Rain totals through Wednesday are expected to near 100-150 mm (4-6 inches) with locally higher amounts.
A cold front already brought widespread 50-100 mm (2-4 inches) of rainfall to these areas Sunday night into Monday, enhancing the threat for flooding as additional rainfall arrives.

Weather Outlook Across Asia

A zone along the southeastern coast of Honshu will get the heaviest rainfall and most widespread flooding, generally from south of Tokyo to Osaka. These areas could receive 150-300 mm (6-12 inches) of rain through Thursday. Even higher rain amounts are possible in isolated areas. As all of this water rushes off the mountainous terrain, flooding will become a significant concern as well as the threat of mudslides.
RELATED:
Detailed Tokyo Forecast
Japan Weather Center
Western Pacific Typhoon Center
While AccuWeather meteorologists think that Etau will make landfall in Japan on Wednesday as a tropical storm, wind damage will be a much lower concern than flooding. Any wind damage would be confined to areas near the center of the storm, most likely over Kansai and Tokai regions of Honshu where isolated wind gusts over 85 km/h (50 mph) are possible.
Rainfall during the second half of the week is expected to lessen across much of Japan, though additional rainfall could still lead to isolated flooding problems in northern Honshu on Friday.
Residents along the western Pacific Ocean should be on the watch for additional tropical threat through the fall, according to AccuWeather's Fall Forecast for Asia.
Meteorologist Adam Douty contributed to this story.