Not that I agree with it, but I was once told an analogy on predicting "Global Warming". If you had cancer, the doctors can tell you how it is going to progress, but not to know how fast to the day to day progression.
However, both my grandfathers and a grandmother had cancer. Two of them beated it against all expectations and died of old age complications unrelated to the cancers.
Going back to the forecasters, who I have very little regard for, last summer was forecasted as to be one of the hottest in record (for where I live) and they could not have been more wrong. Instead of hot and dry it was wet and cool.
If on top of that you want to go the AGW route... well, it becomes a charade.
The strangest seeming part of that item was not that they got it so wrong, but that they failed to stir the AGW pot with such a surprisingly warm day. A golden opportunity to stoke up some good ol' apocalypse fears missed!