We consider the time evolution of a squeezed vacuum cavity field interacting with an initially excited two-level atom via the Jaynes-Cummings model in the Rotating Wave approximation. For large enough initial squeezing, we recognize a new partial revival phenomenon in terms of the quadrature variance product. We show the time evolution of the field quasiprobability Q-function, which provides a quadrature space picture of the partial revival phenomenon. An interpretation of the phenomenon in terms of a certain kind of first momentum of the photon distribution function is given.