The Basics
-Thunderstorms form from convective clouds (but not all convective clouds grow into thunderstorms)
Conditions for Development
The 3 conditions required for the formation of thunderstorms are: (1) unstable air, (2) high humidity and (3) a lifting force.
A lifting force
-an example would be a mountain range, or warm land (which warms air and causes it to rise)
-this lifting force causes air to rise
-air therefore cools adiabatically
High humidity
-presence of moisture keeps air rising
-remember as air rises and cools adiabatically, it condenses and gives off heat.
-this would typically slow down the adiabatic cooling
-but high humidity helps to keep it rising!
-it fuels the growth
Unstable Air
-an unstable or conditionally stable atmosphere
-a STEEP environmental lapse rate
-this helps to keep rising air buoyant, and to keep it rising
-once the air hits stable air (like in the tropopause), then it stops
*Remember: stable air mass = shallow ELR
IFR Rating 