*Note I don't know much about internet stuff, so I may not be using the right terms and such.
As far as I know, that's not possible. lightningweather.com/wxforecast is a directory, which is like a folder on your computer. lightningweather.com/wxforecast.php is the actual page, like a specific file on your computer. If there is some way to do what you want, I would be interested in finding it out, but like I said, I don't think it's possible.