A few years ago, we were visiting friends in Maricopa. We were in their back yard in the evening darkness and my view was to the west. I saw a yellowish cloud that started growing. We were all looking at it then and it continued to grow. The only thing we could think it might be was a launch from Vandenberg. Being former Californians, we were really surprised that we were able to see the launch from Arizona. Our suspicions were supported by a story, with video, on the news that night.
When the sun is down in Phx, but still not too far down, it can back light the exhaust gases quite dramatically.