The strong signals and forecast conceptual model for regional persistent torrential rain in Hunan in June

Based on typical circulation type of regional persistent torrential rain during flood season in Hunan, and using the NCEP/NCAR reanalysis data from 1961 to 2016 and abnormality method, the circulation type in Hunan regional persistent torrential rain in June was identified objectively. The signals for regional persistent torrential rain in Hunan in June were determined and quantitatively expressed by circulation type, regional kinetic ascending and water vapor transportation, and the conceptual model of regional persistent torrential rain was established. Results were as follows. The confidence rate of 43 historical events of regional persistent torrential rain was 81% and the test accuracy of 3 events of regional persistent torrential rain from 2017 to 2018 was 2/3. The conceptual model had certain forecasting ability and could provide technical support for business service of rainstorm forecast in Hunan. According to the conceptual model and combined with the model prediction products, medium and extended range forecasting of regional persistent torrential rain could be carried out.