The stationary wave changes in January and July is found to be very robust. In January, anticyclone pairs in the eastern subtropical Pacific and cyclone pair over the subtropical Western Pacific, and a deep low over the Aleutian region in the upper troposphere are found. The deep low over Aleutian region and the anticyclone over the eastern subtropical Pacific induces an eastward extended subtropical jet which bring more precipitation to Northwest US. The linear model reproduces the stationary wave changes in the GCM fairly well. The main contributors to the enhanced subtropical jet are diabatic heating and stationary non-linearity. It is also noted that the stationary wave changes in midlatitudes are strongly equivalent barotropic, indicating that global warming does not greatly alter the transport of heat by midlatitude stationary eddies. The non-linear baroclinic stationary wave models will help in understanding the nature of the stationary non-linearity forcing seen in the linear model results. We will also explore the seasonality of the stationary wave changes and their maintenance using the linear and nonlinear models.