Reloading page for the HTML plugin

I am using the HTML plugin to display a web page (specifically the rain radar forecast) within a panel. The problem is that the contents do not refresh unless I reload the entire grafana page as apparently the auto-refresh (I have it set to 5 minutes) does not do that.
Perhaps I am approaching this in a wrong way, but I could not find any other plugin that would allow me to provide a source URL to be displayed. Any suggestions would be most welcome!