Weather Blog

Confusion in the skies? Video shows textbook case of wind shear

We tend to think of weather as something that moves in harmony in one direction -- typically west to east or some small variation thereof.

But as this video from Greg Johnson's shows, not on Saturday morning. Oh sure, the clouds at the mid and high levels were flowing along in the traditional west-to-east direction, but down low, we had some rebellious clouds that marched to their own drummer, going in exactly the opposite direction.

The low level flows around here can vary due to our mountainous terrain, especially when we're in convergence zone mode. Here, the low level flow was moving from the east-southeast out toward the Strait.

This is known as vertical wind shear -- when you have wind going in different directions with height. You can see at times on the video where the two layers mix together a bit, causing some brief collision of winds and convection (i.e., it makes a cloud).