Thanks, PJ2, for an erudite and thorough reply.
I think I (and likely many others) may have been led astray by the BBC documentary that came out
before the recorders were found. In it, a hotshot meteorlogist spent quite a bit of effort in demonstrating what he thought the weather was, based on satellite images.
And of course (not addressing CB now) there was the reported "whooshing sound" in the cockpit picked up on the CVR, that BEA speculated was probably ice crystals.