We consider a production stage that produces a single item in a make-to-stock manner. Demand for finished goods is stationary. In each time period, an updated vector of demand forecasts over the forecast horizon becomes available for use in production decisions. We model the sequence of forecast update vectors using the Martingale Model of Forecast Evolution developed by Graves et al. (1986Graves et al. ( , 1998 and Heath and Jackson (1994). The production stage is modeled as a single-server discrete-time continuous-state queue. We focus on the stationary version of a class of policies that is shown to be optimal in the finite time horizon, deterministic-capacity case, and use an approximate analysis rooted in heavy traffic theory and random walk theory to obtain a closed-form expression for the (forecast-corrected) base-stock level that minimizes the expected steady-state inventory holding and backorder costs. This:expression, which is shown to be accurate under certain conditions in a simulation study, sheds some light on the interrelationships among safety stock, stochastic correlated demand, inaccurate forecasts, and random and capacitated production in forecasting-production-inventory systems.