If you inspect the html, you'll see it's loading a number of images sequentially to create the main "animation" image:
I suspect you need to reference a web site that uses a looping .gif format instead of one that's loading a succession of images.
An example is the graphic I insert into my main NPM front page that shows the weather radar loop for my area:
For fun, capture the image section in that map and see what happens when you paste them in as an image resource into a new Widget in a View. Maybe you'll get lucky and one of those image ranges / URL's will be just what you need.
I suspect you'll run into challenges because the page has options to set date and time, and you probably only want something like the last hour or last several hours or days. Getting that to automatically update/roll into current time might be . . . interesting.