If you pull a guitar string and let it go, it vibrates, moving back and forth across its initial position. Changes in density lead to changes in pressure since pressure at a point reflects the weight of air above. Changes in pressure leads to changes in wind since pressure differences cause wind to flow. Changes in wind move warm and cold air around so that air temperatures will change. Instabilities Instabilities are examples of positive feedbacks which move a variable rapidly away from the initial value.
Thunderstorms build due to instabilities based on positive feedbacks.
Restoring equilibrium Nature has a way of seeking equilibrium in the long term. It is common that periods of instability, based on positive feedback processes, ultimately die out and a new equilbrium is restored. A thunderstorm, for example, develops due to positive feedback instability. But eventually, it exhausts the supply of energy, or moves itself into an unfavorable environment for further development. It then dies out and leaves you in a different environmental situation than that which existed during the unstable growthy phase.