Cbs can have high concentrations of water vapor at the top and in the anvil
If that is true then how come weather radar is often unable to pick anvils and CB tops which explains why sudden onset of violent turbulence shakes people up with nothing showing on the radar.
I am not saying you are wrong - far from it. Perhaps it is only tropical storms where tops are invisible to radar due lack of moisture at the higher levels of 35,000 ft plus, while European CB's do have considerable moisture in tops and anvils (?) which are generally at much lower altitudes than their Pacific counterparts.