(or RFD) - A region of dry air subsiding on the back side of, and wrapping around, a mesocyclone . It often is visible as a clear slot wrapping around the wall cloud. Scattered large precipitation particles (rain and hail) at the interface between the clear slot and wall cloud may show up on radar as a hook or pendant ; thus the presence of a hook or pendant may indicate the presence of an RFD. See
supercell .