Rowland Hilder.

Born in Long Island, New York in 1905 to British parents, he spent his adult life living in Kent, England, and became what Wikipedia calls the pre-eminent painter of English winters.

He had 27 colors in his watercolor paintbox, but generally used no more than eight in a single painting. I'm particularly drawn to his neutral tone schemes. Many of his greys were made with lamp black and a touch of burnt sienna or payne's gray, sometimes with a bit of ultramarine.

The subject of countless profiles and biographies, the best brief story of his life I find is in his obituary, in The Independent.