The Coriolis effect

On a rotating object, like the earth, a point closer to the center will be moving slower than a point further from the center. This means that clouds that form near the equator will move at the same speed as the equator while clouds that form further from the equator will move slower. This results in the effect that clouds that form at the equator and move away will appear to be accelerating because the ground and everything around them will be moving slower while they maintain the same speed due to inertia. The same thing also applies in reverse where clouds that form further from the equator and move closer will appear to be slowing down because everything around them moves faster.

Now if there is a low pressure cell that forms in the northern hemisphere which sucks in clouds around it then it’ll spin in a counter clockwise direction because the clouds from the north will fall behind and move to the west while clouds that come from the south will be faster and move to the east. This will result in a counter clockwise spin and the reverse happens in the south where clouds that come from the north will speed ahead and move to the east and clouds from the south will fall behind and move to the west resulting in a clockwise spin. This is also the reason why tropical storms, also known as hurricanes, in the northern hemisphere rotate in a counter clockwise direction while tropical storms, also known as typhoons, in the southern hemisphere rotate in a clockwise direction.