It is a challenge to paint convective cloud. No sooner have you blocked in the cloud structure and colour, but the cloud changes both in shape and colour. Typically the convection is taller and the bases are darker. The taller clouds places some neighbouring clouds in shadow and these take on a grey colour with a tint of burnt sienna. I have a few of these in this painting.
A knowledge of the meteorology of the situation does indeed help but it is not the solution. The fix is to practice what I preach and that is to leave things "unfinished". Get the first attempt right and leave it alone. That is what I did with this bit of summer-time fun. The cumulus continued to develop and by the time I was finished, the scene was overcast cumulus. The little ridge was passing through Brockville so more weather was on the way!
The sailboats came by just at the right time. I wanted to practice what I preach and this time, there was no delicate touch-ups! It is becoming easier to ignore the finagley details as my older eyes don't see it as clearer as they used to.