It was near the end of a rather brutally long day so it is likely I would have been incoherent.
Lawson was a Canadian-born painter trained in New York and Paris. His main focus seemed to be on the natural side of urban, landscapes not of the wild but of the areas we humans most frequent. The work that pops up most when you look for information on Lawson is Spring Night, Harlem River.
His paintings seem to be primarily tempera and gouache. The Prophecy seems so precise and the colors so forceful it doesn't seem to fit with either medium. His works are also not simply of Harlem. His themes move beyond that geography and even across oceans (there are some paintings of African subjects).