About 7:30 in the evening I took the wheel to bring the truck in to Denver. As the sun set lightening appeared to the northwest. Looked pretty. As I drove it moved in front of me. The farther I drove the larger the portion of the sky that was lighting up. Finally I was surrounded by flashes in the sky. At that point the wind and rain started. There were times I had the pedal to the floor and still had to downshift to maintain 50 MPH. Blowing rain, water coming across the road, lightening and dark. It only lasted 15 or 20 minutes but it seemed like hours.