This is the 3rd time in the month. The cold air is overlapping the warm ground air over Japan, which resulted in the 3rd-time tornades cautions in May.
JMA said the cold air is coming over Japan since Thursday, May 17. The unstable condition cotinues until Friday, May 18, 2012.
Please be careful with tornades, thunder, hailing thoughout Japan.
On Thursday, May 17, there are already many reports of thunder lightening & hailing. The weather condition worsened in Yokkaichi, Mie, Japan as well.
This weather may move to Tokyo (Kanto area) in the morning though mid-day.
JMA advised not to sleep near window tonight.