This is a great app for free flying (paragliding, hang gliding, sail plain pilots, etc). A parameter for the thermal strength (for example thermal updraught velocity) would make this app complete for free flight.
One example that people use for the UK is RASP (based on a GFS model). http://rasp.inn.leedsmet.ac.uk/
Perhaps these images could be overlayed onto a windy map? I know there are different RASPs for different regions.
A visual colour based map would be excellent.