According to one or more embodiments of the present invention, a method of forecasting air quality is provided. The method includes determining weather pattern classifications based on global atmospheric information from a global weather model and determining a synoptic scale correction factor in response to the determination of the weather pattern classifications. The method also includes blending the global atmospheric information the synoptic scale correction factor to produce a data set and blending the data set with regional atmospheric information from a regional weather model to generate weather fields. The method further includes blending chemical information from a global chemical model and the synoptic scale correction factor to produce a second data set and blending the second data set into a regional chemical model based on the weather fields to forecast the air quality.