Tornado in Kyushu
A frontal boundary continues to bring rain showers and thunderstorms across Japan today as shown on the radar below. This also brought a Tornado in Kyushu near Fukuoka yesterday killing one person and causing several injuries as it moved through Fukuoka prefecture yesterday. A sake brewery was reported completely damaged while over 30 houses also took damage during this event. 
Tornadoes are not common in Japan yet not unheard of. Commonly with tropical systems the southern Islands will see weak tornadoes yet every once in awhile when cold air moves south from Russia and interacts with warm air out of the tropics and form a frontal boundary that creates the potential for severe weather. Good news with this system is it was well forecasted and a Tornado warning was issued well in advance of this event therefore likely causing a decrease in the amount of fatalities and injuries.
The frontal system is as close to a mirror image to the spring rainy season front and in some parts it is called the Shurin Front, the season that separates summer and fall in Japan, despite the fact it is about a month early. This front will remain in place through the week so defiantly umbrella weather across all of Japan and in to South Korea. The one relief will be if the tropical area south of Japan forms it will disrupt this front and potentially decrease the rainfall briefly, I note briefly because the tropical system in itself has the potential to bring massive amount of rainfall. 
~Meteorologist Robert Speta
For more information on the tornado please check this link. http://mdn.mainichi.jp/mdnnews/news/20110822p2a00m0na006000c.html
Please continue to check back for newer updates and as always stay safe.