In the framework of studies about the relevance of radon progeny measurements for the estimation of the mixing height, here a time series of radon data is analyzed and used for a short range forecasting activity. After a preprocessing of the time series in order to subtract the known periodicities, we perform forecasts of the future values of the residual series by means of neural network modeling. Finally we apply a simple box model to real data and forecast results, and obtain useful predictions of the mixing height during stability conditions.