Gases are made out of particles that, despite being restrained by gravity, have enough energy individually to fly around at high velocity geodesics in every direction.
When a temperature differential is present within the gas the collisions between the hotter and colder components will form current systems where the colder components are disproportionately pushed into slow moving high-density wavefronts.
In three dimensions with a preferred gravitational direction, these cold, low pressure areas will stick to low-altitude areas (like sea level) and hot, high pressure areas will flow around randomly at higher altitudes.
If hot air is trapped at a low altitude with cold air above it, it will push cold air out of the way vertically at wherever the cold air is thinnest, forming a spike-shaped updraft.
When you account for the Coriolis force, these updrafts will rotate as hot air is drained upwards like an upside down whirlpool.
The tropical region of the Atlantic is very hot compared to the air 3km above the tropical region of the Atlantic, so it's all of the above on a colossal scale.
