Because earth is rotating, horizontal winds everywhere except at the equator are deflected to the right or left relative to earth's surface. this so-called coriolis effect arises because the air is moving over a surface which itself is continually turning because of earth's rotation. in the northern hemisphere, the coriolis effect causes wind blowing toward the west to turn toward

Because Earth is rotating, horizontal winds everywhere except at the equator are deflected to the right or left relative to Earth's surface. This so-called Coriolis Effect arises because the air is moving over a surface which itself is continually turning because of Earth's rotation. In the Northern Hemisphere, the Coriolis Effect causes wind blowing toward the west to turn toward the North Western.