What looks like a large Altocumulus Floccus with mamma hence Ac mammatus or a small cumulonimbus. More altocumulus mammatus was observed at sunset as shown in the first thumbnail. This cloud is very difficult to explain as the weather sounding was showing little instability on the day but it might have formed as an upper-level trough was approaching the area. It might have also been another virga similar to the one here taken earlier on the day but unfortunately I cannot conclude one way or the other. The photo on the first thumbnail looks more like a virga admittedly.