The sunset one I painted last night out my back door. That effect with the red sunlight hitting the rain from behind was awesome, but lasted only about five minutes. So I tried to just get the colors and then did the rest from memory. It was done in Sketchbook Pro, but when I got it to the computer it looked too purple compared to what I remembered so I touched it up in Photoshop.
The other one was done near Memory Grove in Salt Lake City. I started that one in Brushes then switched to Sketchbook Pro because Sketchbook has a smudge tool for softening edges.