Mammatus Clouds

Sitting out on the deck this evening, the quality fo light started to change a bit. I looked up from my reading material and noticed that the generic grey sky that was present when I went out to the deck had been replaced by a small stretch of mammatus clouds. I’ve never seen mammals clouds in the early spring in this part of Montana. My usual experience with these is that they form along the bottom of really big anvil clouds. This was a just a small stretch, maybe 5 miles or so. The rest of the clouds were the basic stratus variety- mostly flat and featureless on the bottom. I suspect (but I will never know) that the parent cloud to these mammatus formations was a cummulostratus- that heaping up of cloud and moisture from above might explain why the mammals formed. Anyway- something is always going on outside if take the time to look around