John Constable - Rainstorm over the sea [Seascape study with rainclouds] (c.1824-28)
"This spectacular oil sketch looking directly  out to sea is one of the most remarkable open air sketches that  Constable painted during his visits  to Brighton. He depicted a dramatic  sky, capturing the fleeting effect  of a rainstorm at sea, with  thunderous black clouds, and with a shaft  of sunlight breaking through  to light up the horizon on the left. […] In his biography on Constable, Andrew Shirley observed that  Constable’s sketches: ‘convey an extraordinary force of emotion’ and  that in this work in particular he captured ‘the transient rainstorm,  tremendous but with  a gleam of light, seized in a moment’ (Shirley  1949, pp. 22–21)." Source: National Gallery of Australia