Based on the analysis of fog continued time forecasting results calculated by interpretation equations obtained with PPM technique, a large number of forecasting factors constructed by output products of numerical prediction and related to fog maintenance are designed and then analyzed by a step-wise regression method in order to found a set of MOS ( interpretation) equations for prediction of fog continued time.Finally, an integrated forecasting scheme is established for operational use A comparison between forecasting results by PPM interpretation equations and those by MOS integrated forecasting scheme shows that the forecasting performance is improved obviously by the latter