Using the diagram in the reader about the whaether or hot air balloon we learned how the air inside the balloon expands as it rises eventually to the point where the pressure is so great that it pops the balloon. When an air parcel finds itself warmer than surrounding parcels of air, it will spontaneously rise. High dew point helps make air unstable. Dew point temperature maps cans show areas likely to be unstable. Air that is lifted is cooled but not as cool as the air around it, and it rises.
Warm air wants to rise because it is warmer than the air around it at the same elevation.
This unstable state causes clouds to form. The chief threat from a cummulonimbus cloud is cloud to ground lightning, flash flooding, and tornadoes. For example, the Texas Panhandle. It's anvil was at the ground to about 50,000 ft. It produced a tremendous amount of rain and hail.