Today I wanted to do something similar.
Using cobalt blue I started the bottom layer of thunderheads with horizontal strokes. Then I painted in the upper edge of the next layer of clouds. Nest a third layer was painted softening the colour downward.I added Antwerp blue to the cobalt blue and painted in the sky behind the clouds leaving the final edge of the highest layer of clouds.
Once the clouds were dry I painted raw sienna into some of the clouds to give a little warmth to the picture.
I will probably add trees into the foreground to have them stand out from the background clouds like I did with the ACEO.
I will post this painting when is completed.
