Looks like the first typhoon of the season is on its way, according to this website: Hurricanes, Typhoons & Tropical Cyclones Worldwide (not sure what has happened to their map - looks like someone splashed green paint across it).
This was the map as on Saturday lunchtime. Looks like a near miss for us (near Toyko/Yokohama - the southwestern corner of Japan). I find their forecasts to be very good, despite all the disclaimers. Sorry, it's not very readable when scaled for the web page.
Last year we had 10 hits on the Japanese main land - killing over 100 people and costing almost $7billion - which is almost double the previous record of 6 hits in a season and three times the average number (there are about 50 years of good records). The long range-forecast for this year is below average, though (I've no idea how accurate this site is - it is just the first thing google threw up). No-one's sure about what sort of influence global warming will have - it seems quite plausible that typhoons will increase in number and magnitude, but it is not certain and the variability is so high that any signal in the data cannot be seen yet. I'm sure it will continue to be a hot topic in climate research for some time.