What is the explanation of this snow and rain?

Snow shower is a kind of snowfall with short (sudden) snowfall time and sudden start and end time.

Rain and snow mostly come from cumulonimbus, cumulonimbus and cumulonimbus stratocumulus. Snow showers are characterized by sudden stop, that is, they can't stop for a while, and their intensity changes greatly. In the process of snowfall or snow stopping, air pressure, temperature and wind force will also change obviously.

From the color and appearance, there is no difference between snow and snow showers, but the intensity changes of the clouds they form are different when they fall, and the individuals with snow showers are often larger than those with snow. Note that when there is a snow shower and there is glaze on the conductor of the conductor ice shelf, sleet should still be recorded.

Formation conditions (taking the eastern part of Shandong Peninsula as an example):

1 There is a certain intensity of cold air, that is, the temperature should be quite low. This is the primary condition for the formation of local snow showers. In winter, the temperature is low, the seawater temperature is low, Tw-T is large, and it is easy to snow. So at the same temperature, it is easy to snow in 65438+February, and it is not easy to snow in February, just because the sea temperature in 65438+February is higher than that in February.

There is a certain intensity of northwest airflow. After the cold front crosses the border, the northwest wind between the ground and the upper air in Weihai is more consistent. If there is no northwest airflow or the northwest airflow is too weak, the water vapor at sea cannot be transported to the shore, so it cannot snow. If the Nw airflow is too strong, the ground wind speed is very strong, which is not conducive to snowfall.

3 favorable weather situation. If the height of 500mb at this station is a warm area under the control of Sw airflow, there will be no local snow showers until the sea of clouds in high school disappears.

In addition, positive vorticity and positive vorticity advection are the same as general precipitation. The non-divergent layer is a relatively strong positive vorticity advection, and the ground map shows that there is obvious cyclone bending in the Yellow Sea and Bohai Sea. At this time, rain and snow are generally strong and last for a long time. On the contrary, if the above sea area is controlled by a high pressure center or ridge, there will be no snow shower or only light snow from another star.