Since I started flying I’ve always been amazed at how quickly the winds increase in speed as you get higher. The site below is well worth checking out if you want to look at wind speeds at various altitudes. It’s a bit like Google Earth, in that you can zoom and pan easily.
Click on the “earth” button (lower left) to look at different altitudes and speeds.
(admins - please feel free to move this post into a better category. I wasn’t sure of the best place for it but wanted to share)