The people of Japan are in for a big hit, but they have some luck on their side, nonetheless. I will share some thoughts about Roke.

The typhoon Roke, was a super typhoon, with max sustained winds at 107 knots (198km/h), and with gusts over 200km/h. This is equal to a category 4, major Atlantic hurricane.




Now why are they lucky?
Well, Since Roke was a super typhoon, a category 4 on the SS scale, it is now going through an ERC (eyewall replacement cycle), which can be seen on the satellite animation. During this cycle, the main eyewall is getting smaller, so some of the outer thunderstorms can strenghten, and form a ring of thunderstorms, that looks like an outer eyewall. Because of the rotation and wind fields, it slowly moves inside, closer to the center of the storm, and so disrupting the moisture intake to the center eyewall, and can also disrupt the circular momentum of the storm. The strongest winds are around the main eyewall in the center, so during this cycle, the storm usually weakens, which is happening with Roke at the moment. So he weakened from a category 4, to a category 3 typhoon, and will further weaken to a strong category 2. The outer eyewall soon replaces the inner eyewall, so the storm can form a new inner eyewall, and begins to re-intensify. But with Roke, the intensification will not happen, because it will make landfall and will interact with the land, before the ERC would finish, and intensification could start.
So Roke will hit Japan as a category 2 storm. But they will still have to deal with huge amounts of rain.



Here is a visible satellite image of Roke, before the ERC.



Best regards.