"A warm spring rain" and "a cold autumn rain". Why do you say that?

China has always been a rainy country. Except for some provinces in the northwest, it is almost always heavy rain. However, the southern region is affected by heavy rains and floods every year. Explain that when the rainstorm is coldest, it is related to which season it rains, and the corresponding weather system is different at different times.

Why is there a rainstorm in our country?

China has a monsoon climate, from late spring to midsummer, with cold air in the north? Losing ground? Cold and warm air meet in South China, and the rain belt moves from north to south. It is always rainy in South China from April to September, especially from April to June. From the rain belt to the north, from late June to early July, the rainstorm period in the Yangtze River basin is also called the rainy season, and the rain belt reaches the Yellow River basin in late July.

When is the coldest before, during and after the rainstorm?

China has a vast territory, even in the same place, it is only 3500 meters away from different places, which is another weather. This is related to the frontal system in the weather system.

As the saying goes, an autumn rain and a cold represents the rainstorm in summer in the north, the sandstorm in the north and the cold wave in winter, which is actually the performance of the cold front crossing the border. The cold front is the front where the cold air mass actively moves to the warm air mass.

What does the front here mean? Heads? And then what? Frontline? The front is the intersection of cold and warm air masses.

Pictured: Cold front profile.

Generally speaking, the density of cold air mass is greater than that of warm air mass. When the cold air mass actively approaches the warm air mass, the originally light warm air mass will be lifted by the cold air mass. In this process, the heating mass will gradually cool down, the original water vapor will condense into clouds, and then it will rain.

Therefore, most of the precipitation of cold front is concentrated in front of the front, and the cold front is the performance of cold air, so the precipitation of cold front is mainly cold after rain.

Another way of saying it is. A spring rain and a warmth? It refers to the warm front.

Because the moving speed of the warm front is slower than that of the cold front, when the warm air mass moves to the cold air mass actively, it climbs slowly along the cold air mass, so it may form continuous precipitation or fog.

The influence of warm front in China is small, but what is the influence of warm front? Cold? It's just ahead, but because of the long-term cold air, this cold can't be felt.

Pictured: warm front outline.

There is also a cold front, also called fast cold front. Because of its fast moving speed, steep front and strong air uplift, it is usually accompanied by cumulus clouds and fluctuating clouds. So generally speaking, there will be thunderstorms, and this cold front usually appears in summer.

So it's warm before the front, cold after the front, and it's even colder when it rains. That is, the cool feeling after a sudden heavy rain on a hot summer day.

To sum up, cold before rain is a warm front, rain is a thunderstorm, and rain is a warm front. Rainstorms are actually related to weather systems, and each weather system has its own laws of growth, movement and extinction. Although the weather system is clear in a few words, the reality is far more complicated than we thought.

Is it a sign of dawn in Shanghai that tap water will be turbid?

In the flood disaster caused by continuous rainstorm, there will be more organic matter, inorganic matter, sediment and other substances in the water than usual, and the tap water at home will turn yellow with dirt. Many people think that dirty water released by tap water is a precursor to heavy rain.

This is not right. There is no intersection between rainstorm and tap water, and rainstorm will not affect the water quality of tap water in advance. Although there is a lot of rain in rainy days, it affects sewage discharge or sewage overflows into rivers. However, the river is swift and the sewage is diluted by rain, which has little effect on the water quality.

On the other hand, there are four passes for drinking tap water to enter the waterworks and then flow into users' homes from the waterworks. Only when it meets the standards can it be discharged.

finally

Du Fu once wrote a poem "The Cottage Was Blown by Autumn Wind", which actually described the phenomenon of cold front crossing the border. In August of the lunar calendar, the weather gradually turned cold, and the thunderstorm blew away the thatch on the roof, not to mention Du Fu's poverty.