Here is a fun exercise to experiment with deriving winds by tracking cloud features between two visible satellite images. The images are 30 minutes apart. You can switch between the images by using the step button below the images. You might want to practice using this applet.

The cross and X are used to identify targets. You can move these markers by placing your cursor over them and holding down the left mouse button until you find a cloud feature to track. You can tell which scene you are on by the color of the markers, yellow indicates which target indentifier (cross or X) will be moved when you click the step button.

At the top of the image are listed three variables:

You can compute the wind speed by dividing the distance between targets by the time between the images. Be sure to check your units! (Do you want your speed to be in miles per hour, kilometers per hour, or kilometers per minute?)

Note that at each station, the current weather (symbol) and visibility (in miles) are plotted.