An extension assembly for a processed crop storage tank on a combine. A closure assembly for a top opening on the tank has at least one panel with one surface area that is exposed to bound a part of an exterior space above the storage space with the closure assembly open. The extension assembly has a first extension panel with a first surface with a first area and a connecting system through which the first extension panel is operatively connected to the combine. The first extension panel is changeable between a deployed position and a stored position. In the deployed position the first surface and one surface define a combined exposed surface area that is greater than the first area of the first surface. The combined surface area is exposed to confine processed crop in the exterior space with the closure assembly open.
