Don't you just hate it when you're in a place that you think is so photographable yet you struggle to capture what you are seeing and feeling. That's especially true in challenging lighting situation like this.
A couple of things to try:
1 - You've made an interesting decision to shoot portrait instead of landscape. Why don't you try exaggerating the effect by making the composition even more vertical. Try cropping left and right, or just from the right until the image feels tall and the clouds recede from nearly straight overhead into the distance.
2 - Because of the bright sun, the rest of the image is a little underexposed. I'd like to see more form and detail in the clouds. You may be able to recover some detail and reduce contrast a little by creating an HDR from a single image. Simply make two copies of the image and overexpose one by a stop (or a stop and a half) and underexpose one by a half stop. Bring the three images into an HDR program and slide the sliders until you get something interesting. I did that to the following image and was able to salvage something from it:
Good luck!