I tracked down the news clipping that has been the source of the alleged proof we have that the plane encountered turbulence:

"A Paris airport official told AFP there appeared to be 'no hope' that the jet would be recovered safely.

'In his last communication, the captain said there was turbulence and afterwards contact was lost,' the official said, speaking on condition of anonymity."

I have no idea what this "last communication" was because every single other news outlet says that the last communication took place without the pilot/captain warning of anything at 10:33PM Brazil time with Brazilian Air Traffic Control.

If this was the last contact with the plane, other than the automated signals the plane sent out later on, how does Air France know for certain that the plane encountered turbulence?