It's hard to believe (for me, at least) that these were taken on the same day, yet they were.
One of the things that motivates me to get out and shoot is the ever-changing skies, particularly at this time of year. The March winds always create a bit of drama, which urges me to get out there with the camera a few times a day -- oh, the tyranny of the lens!
I realize I'm obsessed with my "windshield filter" (and consequently, telephone poles and roads). When I'm driving, it's like I'm looking at a giant canvas and I can't help but pull over and take a shot when something strikes me. Also, the windshield lends another layer of atmosphere to the scene. Invariably these shots turn out too "green" and I have to correct that with a curves adjustment to the green channel.
For all three of these shots, I did the usual curves adjustments, pumped up individual colors like blues, cyans and yellows. On the second and third shots I added a very tiny bit of diffuse glow to the clouds. (They were already glowing quite a bit so I took it easy there.)
Fantastic Photos! You have a great artistic eye. How much PhotoShop work do you do? Is it mainly in enhancing color?