For those despairing the end of summer, look no further than this collection of Walter Plate’s beach paintings, completed in the years leading up to his early death in 1972. In his short career, this Abstract Expressionist garnered major recognition alongside Mark Rothko and other modernist masters. On loan from the artist’s estate, the paintings in “East End Abstractions” apply his signature gestural brushwork, master coloring, and figurative elements to maritime themes. —J.V.