This is the best radar that I know an use it almost daily, it covers the continental 48 states and you need to refresh the page every few minutes. You can search for the area of interest and move your mouse over that area and click, it will change the window to that local radar and from here you can zoom in more. It shows all warnings and watches boxed areas. It is pretty cool. Check it out yourself.
[link to radar.weather.gov]