Without wishing to be at all patronising, honestly
, the clue lies in the name.
Clouds and thunderstorms tend to be associated with convective currents. That is air currents generated by a vertical difference in temperature. This could be strong solar heating over relatively flat countries (eg northern France, UK etc, or air masses being pushed up over mountains (eg the Alps), with heating effects adding to the energy input) or warm air masses being pushed up over cold air. Not to be messed with, any of them, but normally easily visible, either with the naked eye for isolated cells in daylight, or with weather radar for night or embedded cells.
Clear air turbulence, CAT, as the name implies, is normally invisible and NOT detected by weather radar. However if does tend to be by associated with strong jet streams, and normally when crossing through, or into or out of, a jet stream core. Quite often it is forecast, and our SIG(nificant) Weather charts show the forecasters best guess as to where it may lie. However we are often told it could be anywhere, hence standard advice to keep seat belts fastened if you don't need to move about the cabin.
Sorry for such a short and incomplete answer, but it does take up quite a chunk of met theory for any level of pilot's licence.
Hope this helps.