Why is it so cold today?

Because of the cold wave, the ground high pressure behind the cold front in the whole process of the cold wave mostly belongs to the thermal asymmetric system, and there is strong cold advection in front of the high pressure; The back part is warm advection, the temperature advection in the central area tends to zero, and a few high pressures are always cold. It can indicate the strength of cold air, and the central moving path can be used as the moving path of cold air.

the outbreak of cold wave has different characteristics in different regional environments: in the northwest desert and loess plateau, it is characterized by strong wind and little snow, which easily leads to sandstorm weather; In Inner Mongolia grassland, it is windy, snow blowing and low temperature weather; In North China and Huanghuai areas, cold waves often come with snow and snow; In the northeast, it is characterized by more violent winds and heavy snow, and the snowfall is the highest in the country; It is often accompanied by cold wind and bitter rain in Jiangnan.

Extended information:

The cold wave is a large-scale weather process, which will cause a wide range of severe cooling, strong winds and snowstorms along the way. The disasters caused by the cold wave, such as strong winds, frost, snowstorms and rainfalls, have a great impact on agriculture, transportation, electric power, navigation and people's health. Cold wave and strong cold air usually bring strong wind and cool weather, which is the main disastrous weather in China in winter. Cold waves and strong winds pose a great threat to coastal areas.

The rain, snow and freezing weather brought by the cold wave do great harm to transportation. For example, a cold wave process in late November 1987 caused the turnouts of many stations under the jurisdiction of Harbin, Shenyang, Beijing, Urumqi and other railway bureaus to freeze, the tracks were buried by snow, the communication signals failed, and the train operation was blocked. After the rain and snow, roads were frozen and skidded, and traffic accidents increased significantly.