What attracted me was basically the silhouette of the sky made by the building. By the way, the sky wasn't that dark, although it was cloudy and going to rain. The shadow was added from imagination to give the sketch a bit more depth.
I'm trying out the Waterford watercolour paper for the first time and I really like it. The cold press surface absorbs water well, and brings out the texture of watercolour beautifully. The paper is a bit off-white which I'm still getting used to.
WN watercolours, Uniball Jetstream, on Fabriano 12.5 by 9.5 inch 200GSM watercolour paper
For today's sketch, I tried to use as few colours as possible for mixing. So I used
Perm Alizarin Crimson
Mixing green with French Ultramarine and Yellow Ochre results in a very dull green that's almost usable. Having Viridian is quite convenient. I also used Cadmium Yellow and Cadmium Red for the metal of the lifting crane.
I've a comment on Facebook asking my approach to this scene. With any complicated scene, patience is the key. The slower you draw, the more accurate your drawing will be. Of course, it will have to depend on the amount of time you have. As you can see from my lines, I was rushing quite a bit to finish this within 2 hours.