Either show the tabs or favorites in the top bar
It took me quite a while to figure out how to get back to the forecast from the Wundermap ... at least show the favorites so it's easier to flip back and forth between the map and the forecast!
We've added a favorites menu to the beta version of the WunderMap: wunderground.com/wundermap/beta
It's the star icon next to the location bar. Through the menu you can jump to your favorites on the map or to the conditions/forecast page for each favorite.
You may be interested in voting for this item. It's gaining momentum: