Abstract: Based on the routine observation datas and NCEP reanalysis datas, a comparative analysis of two cold rain, snow and freezing weather processes in Hunan province in January 2018 was carried out. The results showed that there were many kinds of disastrous weather during the process, such as blizzard, freezing rain, strong cooling, northerly gale and thunderstorm. The process on January 24 to 31 had a wider range of influence, stronger intensity and longer duration than the process on 3 to 8. The dynamic condition and thermal condition was different, and it was pointed out that the thunderstorm and snowstorm occurred in the north of central Hunan province on January 27. The analysis showed that front area at 500 hPa, the strength of cold center, the cold advection intensity in 850 hPa, the intensity of cold high pressure on the ground and the pressure gradient at the front are of great significance for the determination of the intensity of cold air. Humidity and temperature stratification are the key factors for the transformation of the phase state of rain and snow in 700 hPa in south China.

Key words: cold rain, snow and freezing, comparative analysis, forecast the starting point, thunder and snow phenomenon, Hunan province