Group 1 - The core viewpoint of the articles highlights a significant weather event in China, with a large-scale rain and snow weather process expected from January 17 to 21, affecting various regions including Xinjiang, the northwest, and central and eastern areas [1][2] - The Central Meteorological Observatory predicts a drop in temperatures across the northwest and central regions, with strong winds expected in the Yangtze River basin and northward areas, and rain and snow weather in the eastern northwest, North China, and Jiangnan regions [1] - The forecast indicates that the minimum temperature line will move southward to areas from Guizhou to southern Jiangnan by the morning of January 21, with significant snowfall expected in several provinces [1] Group 2 - The current cold wave process is characterized by a larger range of rain and snow compared to previous cold waves, with early rain-to-snow transitions and prolonged snowfall durations in northern regions [2] - The Ministry of Agriculture and Rural Affairs and the China Meteorological Administration have issued frost damage risk warnings for winter wheat and rapeseed, advising farmers to take preventive measures against frost damage [2]