Educational - Cap Back to: Weather Q & A In order for
thunderstorms to develop, the air near the surface must be
buoyant. Just like air bubbles in water. Since air is less dense
then water, any air bubbles released in water float to the
surface, they are buoyant. So, think of thunderstorm clouds as
being almost like those air bubbles. When the air near the
surface becomes buoyant, it bubbles up through the atmosphere.
What makes air buoyant? It has to be less dense then the
atmosphere surrounding it. Air is less dense than water, so air
is buoyant in water. Warm, moist air is less dense then cool
air. So, the air near the surface needs to be warm and moist,
and the air above needs to be cool and dry. As the air rises,
the pressure of the atmosphere surrounding it decreases (there
is less atmosphere above pressing down), this causes our warm
moist air to cool. So we have another concept to remember: when
air goes into an area of lower pressure, it cools. When air is
compressed (into an area of higher pressure)