Ding! Ding! Ding!
We have a winner!
The proper term for it is "sensitive dependence upon initial conditions". It's also known as chaos. Long term weather prediction is impossible. That doesn't mean that it's just hard. The facts are that the universe just isn't made such that trowing a few constants and variables into an equation will allow you to predict chotic events like the weather, or atomic decay.
Isn’t it funny to see how people allways fall for that ?
Seems to be hard to understand that modells to predict a rising or falling long term average temperature HAVE to be easier and more precise then a weather forecast modell.