Our numerical simulations of this case have revealed a new mechanism responsible for wave genesis. The Penn. State/NCAR MM5 mesoscale model, run at 6 km resolution, successfully captured the lee cyclone movement, dry airmass development and gravity wave formation over Kansas. Simulations with key physics omitted have revealed that evaporation of precipitation from the weak rainband at the leading edge of the dry airmass was essential for wave genesis. Evaporation-induced subsidence above the frontal inversion led to surface pressure falls and gravity wave initiation. In the model, as in observations, a long-lived wave of depression developed, remaining tied to the dry air boundary and the rainband. MM5 90s time series data revealed a region of highly (>0.9) correlated surface wind and pressure perturbations accompanying the wave. A transition to wave of elevation occurred as deep convection developed in the model, and significant precipitation reached the surface. The evolution of the dry air mass, cyclone, speed maximum, rainband and gravity wave will be discussed in the hours leading up to and following wave genesis.