This is basic data and not for navigation. Data may not be reliable. In other words no one should depend their life on this data. If you are going to use it on your web site you should disclaim the data.
Positioning is the key to overlaying the images. The images and overlays are each in a div tag with 0,0 abosulate positioning. On this page I also used a "wrapper" div to position the image on the page.
If you are going to use this on a web site you may want put a meta refresh on the page. Probably every hour or so. You can do this on your web page by placing the following code between your <HEAD> tags:
Feel free to use this data to build a radar image for your website however data not for re-sale.