Zipser states that updrafts are usually strongest in the upper troposphere compared to lower levels
(is the bit immediately before...)
Originally Posted by HN39
Tim Vasquez' analysis mentions that "updraft velocities of 20 to 40 kt occur occasionally" in oceanic equatorial cumulonimbus clouds.
There is no evidence at all that these updraft velocities existed in the CBs that AF447 was trying to avoid, nor that they were actually encountered.
This was discussed in the first thread very shortly after the accident.
As was pointed out at the time, 20kt is only 10m/s. I say "only", as many glider pilots will be familiar with benign - if somewhat exciting under a paraglider! - climbs of this type at low levels. On a decent, post-cold frontal day in the UK - not exactly known for the relative strength of its thermals - it would be disappointing not to get climbs of 5m/s under small, perfectly benign, 10 minutes later they're gone, fluffy little white cumulus clouds. If "updrafts are usually strongest in the upper troposphere compared to lower levels", then 20 to 40kt seems quite a conservative estimate.
It would surprise me - and I suspect most glider pilots - if you could find any self-respecting cumulonimbus that *didn't* contain updrafts of at least 20kt.
EDIT: Note that I am *not* arguing that a strong updraft caused the zoom climb or had any other bearing on AF447, merely re-iterating, for the benefit of latecomers, comments made a long, long time ago on the above analysis.