Did you know that there was a cloud appreciation society? Well neither did I, that is until Shelley forwarded this link to Shawn. And we now have a new cloud on our immediate horizon, the asperitas or asperatus (not sure which) has been deemed a new classification. Welcome to our sky, friend!
Has some mammatus characteristics I think. Remember the clouds I shot at the Griffith Park Observatory? More info on these new cloud structures here.