The Extended-Range Process Prediction Technique and Application

This paper introduces the Method on Low-Frequency Synoptic Weather Map and on low-frequency wave in key region, the verifying indices for extended-range weather process forecast , the related operational system(MAPFS 2.1) and their promotional application, and further works for verifying of the heavy rainfall processes during flood seasons in 2013-2016 and the heavy cooling processes (cold air processes) during winters in 2015-2016.The results indicate that the accuracy rate of the heavy rainfall process forecasts and of the strong cooling process forecasts were about percent of 67.3 and 43.2 respectively, and correspondingly their scores of Zs and Cs reached 0.153/0.130 and 0.139/0.09 in turn. The Low-frequency synoptic weather map method accurately forecasted the heaviest precipitation process for each year in 2013-2016. This suggested that the approaches have the advantage for predicting the extended-range weather process indeed and have tremendous room for improvement. The MJO-activity -depending approach of the pentad precipitation anomaly over Shanghai during flood seasons made a delightful encouraging performance for 2014-2015 with Ps score of 58 and supplied the valuable predicting background in determination of extended-range weather process and the beginning and the end of Meiyu rain.