Unexpected Mammatus

I stopped off at a store on my way home from work on Tuesday, March 18, 2014, and as I prepared to get in my car to go home, I noticed mild but very distinguishable mammatus formations in the west sky. Considering the fact that most mammatus form under the anvil of a cumulonimbus cloud, this was a little unusual. Weather conditions at this time more winter like: 48 degrees F temperatures, 64% humidity, 35 degree dew points and winds out of the southeast at 15 mph. The top image was captured at 3:14 PM from Hy-Vee Drugstore at Boyson Road and C Avenue NE in Cedar Rapids, Iowa. The middle image was shot about five minutes later from Bowman Woods Park. The bottom image is a radar capture of the moment.