If I am concerned about snow-rain transitions, especially when I have to travel up from the south, these are my favs:
http://radar.wunderground.com/data/6...dara5_anim.gif
while WC may stink in general, they still do have some good basic data
http://www.weather.com/weather/map/i...page_flash_map
and Environment Canada is pretty good too
http://www.madriverglen.com/weather_data/canada.jpg