TORNADUS ENCOUNTER GLITCH I've entered, and Exited the Gate to Routes..

Question for Pokemon Black

TORNADUS ENCOUNTER GLITCH

I've entered, and Exited the Gate to Routes 9, and 10 from Opolucid City to find TORNADUS,
And the Bulletin boards' say: "A very Unusual thunderstorm is happening" on a certain Route,

But when I enter that Route from the Gate to Opolucid City, the Storm is happening in a totally different Route.

Ex: Route 10: A very unusual and Strong Thunderstorm is happening.

But when I enter Route 9 from the Gate to Opolucid City, the Storm is happening there instead of Route 10.

In Short, if the Bulletin says:
Route 10, and the storm is on Route 9

Route 9, and the storm is on Route 11

Route 11, and the storm is on Route 10

Any Idea as to why this is happening?
Is it a Glitch or something?

:S