I actually went out to get a shot of a really nice rainbow.
But the scene of the clouds over the mission was the
best opportunity of the day. The
clouds were bunched around the mountain. As the sun set,
it was shining under them through the heavy rain close
the mountain. It made for some particularly dramatic
lighting. As you can see from the streak of car headlights
on the right of the photo, this was not a short exposure.