I think I can a bit.
The overture stats are coming from July.
That's the rainy season in Japan & afterwards there had been lots of Typhoons with Thunder Storms.
You can say it's a seasonal Domain but certain times of the year those keywords will hit the roof with searches.
Just like in the winter Blizzard might be searched in Hokaido not really Tokyo but definitely not at all in July.
I have 台風情報.com (xn--kprw2hhrjcp4d.com) in my portfolio. Which translates to "typhoon information".
It was one of the top Google Japan results one month last year as reported in google Zeitgeist.
I don't completely understand the use of the Chinese characters for a Japanese term?? You know more about Kanji and simplified/traditional than I do...
I already have it as it did 578970 on Chinese Simplfied Overture in July. Only 251 on the Japanese Tool, so it is clearly much more meaningful in Chinese.
Obviously something to do with Thunder. It appears to have software conitations.