THE attack on Mosul, Iraq.

I have known for weeks and weeks about the intention of the Iraqi army to attack Mosul.
Now, I read this:

http://www.reuters.com/article/us-mideast-crisis-iraq-mosul-idUSKBN12G0GN

This attack is necessary because IS has Mosul. So, as one of the oldest cities in the world, the Iraqi.gov.iq has to recover it. 

It you are really serious, when and where in the annals of military strategy is it advised that you forewarn your enemy that you are coming.
There is something that just does not smell right especially in conjunction with such an extended delay in the actually doing of the attack.
You can sense the dark hand of the US CIA behind these shenanigans.