Typhoons. They're big, they're bad, and they're here.
Wikipedia defines typhoons as "mature tropical cyclones." They tend to appear in the Northwest Pacific Ocean. Typhoons form throughout the year, although the summer and fall months are the heaviest months of the year; in 2004 there were as many as 13 typhoons, although not specifically in Japan. However, Japan does experience a great deal of them. The area where Japan lies accounts for a third of all annual tropical cyclone activity. In fact, The Japan Meteorological Agency is tasked with the responsibility of issuing typhoon warnings to the entirety of the Western Pacific for the last twenty years.
As I speak, around 5:30pm Tokyo Time, The Japan Meteorological Agency has issued a typhoon warning for Kanto, Tohoku and part of Hokkaido, three major geographical regions of Japan. I expect there will be some flooding, although nowhere near where I live, fortunately. My own village, H--, is characterized as suffering from "Heavy Rain, Storm, Flood, Thunderstorm, and Dense Fog." However, these are general terms since the meteorologists cannot individually check every village, town and city in Japan. In fact, what H-- is experiencing right now is simply heavy rain. If you click the previous link, you'll see that all of Fukushima is described using the exact same five terms.
By tomorrow, the typhoon will have moved outside the scope of Japan and northeast, toward (if I'm correct in my geography) the Sea of Okhotsk. They canceled school early today, but hopefully I won't have any problems navigating the waterlogged streets of my village tomorrow morning.