Turn on your faucet—any faucet. Start with just a slow stream of water. See how smooth, transparent it is? That’s an example of laminar flow. Now, accelerate it by opening the taps fully. Notice how it roils, as a brook after a rainstorm. What you see is the essence of turbulence.
Flying through air is essentially the same act as “flying” a submarine through water and—like the oceans—our atmosphere is composed of moving, rising, sinking, swirling molecules of air we call wind. Why? Because, well, we are moving, the earth around the sun, the earth on its axis…you get it. As huge swaths of air heat, rise, swirl, eddy out and sink, weather happens. With any weather, be it clear or cloudy, stable or unstable airmass, there can be turbulence. Take a look at a surface analysis or constant pressure chart. If pressure gradients are strong (isobars close together), you can expect lots of wind and turbulence.
