I think these might be altocumulus clouds. They were there as I did a late afternoon bike ride a couple of hours ago. They were gone soon after.
In the photo below, I liked the way the trees were silhouetted and a little sunlight touched them. But the way it came out here is very different from what I saved. I guess you always have to play with the screen - the street should be very much in the shade.
J was walking about where I took the cloud photo about 30 minutes earlier. A guy on a fancy bike with biking shorts and shirt came speeding along toward her (he was in the bike lane and she was on the side walk) when all of a sudden he flew over the handle bars and hit his head on the street. She called 911 on her cell phone and waited until they arrived. She said he didn't get up, his head was bloody, and he was talking but not too coherently.
This is a flat, recently repaved section with a good marked and separate bike path and little traffic on a wide street (not the one above). It was light still when he went down, but J said it was dark when the emergency folks arrived. It was just at that time between sunset and dark. So even on a day with great weather, on a good smooth, level road, with no traffic around, something can happen. I'm not suggesting people should stay in bed, but wear your helmet! J talked to the emergency folks and then walked on home before they took him away.