Roger's SkyPix

Mini Cloud Atlas

Altocumulus Castellanus

Altocumulus Castellanus

Crepuscular rays of the setting sun bathe altocumulus castellanus (ACCAS) clouds in their golden glow, as another day ends on the Minnesota glacial prairie. ACCAS is a sure sign of an unstable layer aloft, whether or not any deeper and lower convection ever takes advantage. In the distance, a low stratus band signals the approach of a cold front.

4 N Clarkfield MN (7 Jun 4) Looking WNW