Canon 5D II ISO 100 - 0.67, 1/200 sec f6.7
I found the weather in Yellowstone to be similar to here in UK - but more extreme, it was cooler and it was hotter and the weather conditions changed more quickly and dramatically. I tried to capture the change in weather conditions it was lovely sunshine one minute then the next there was quite a shower then it cleared up again.
I have done quite a few things with Nik filters, saturation, grads, tonal details also I used Andrew's previous suggestion on the cyan in the sky.
(Steve if you are looking - yes I saved the TIFF!!)
All C&C welcome.