As long as you ask for the same minlat, minlon, maxlat, and maxlon map extents in both your Google maps and your Wunderground service calls, they should match up. Here's how we do it:
Actually the url in your post was incomplete as far as I could read.
But not to worry, I switched to Wunderground Map fullscreen and have everything I need. I had to modify the html as it came through my code but every thing works fine.
