(1) the development of clouds from fair-weather cumulus to giant cumulonimbus(2) A cumulonimbus has drifted over the spires of downtown, where it hangs like a vast gray anvil.(3) As air rises in a large cumulonimbus or thunderhead cloud condensation occurs and all three forms of water are present.(4) The rising air cools and produces towering cumulus and cumulonimbus clouds.(5) First, thunderstorms are birthed by cumulonimbus clouds.(6) The rising air is associated with a region of low air pressure, towering cumulonimbus clouds and rain.
