Abstract:Based on precipitation and weather phenomena data from Kunming Station in winter from 1952 to 2013, the climatic characteristics of winter snowfall in Kunming are analyzed. In addition, using surface and upper air data, six physical quantities such as temperature at 500 and 700 hPa, 0℃ level height, geopotential thickness between 500 and 700 hPa, daily lowest and average temperature at surface are selected. The phase of precipitation and snow is analyzed, by using the principle of highest TS score to determine physical quantities’ threshold range. Different weights are offered to each criterion, using weight linear method to set synthetic criterion of snowfall, through different combined experiments on snowfall criterion of six physical quantities, and considering the operational application of synthetic criterion. Finally, three single criterions are selected, that is, temperature at 700 hPa, geopotential thickness between 500 and 700 hPa and daily lowest temperature at surface, and combined into synthetic criterion. In addition the precipitation phases during 13 rainfall weather processes in 2014 are tested by using WRF model. The results show that synthetic criterion could provide valuable reference for objective forecast of precipitation phase in winter, Kunming.