As we all know, the cold front is the most common front in China. Why are cold fronts mostly violent storms?
The cold air at the back front moves much faster than the warm air mass. It hit the hot air mass, forcing it to rise strongly. In the upper layer, warm air slides along the front because it moves faster than cold air. Because the front is located behind the trough or near the trough line, the rising motion near the front and the sinking motion of the upper front are further strengthened. Sports. There are strong cumulonimbus clouds near the front of the cold front in summer, and convective unstable weather such as thunderstorm, hail and squall line appears. On the high-altitude front, no clouds usually form. Therefore, the fast-moving cold front cloud system presents a long and narrow cumulus belt arranged along the front. The fast-moving cold front lasts for a short time. This cold front mostly occurs in winter and spring in northern China.
Why is the cold front dominated by storms? What are the types of cold fronts?
① Cold front weather of the first kind
After the ground front, it began to rain, the wind speed suddenly increased and the weather was bad. After the upper trough passed, the precipitation gradually stopped and the weather began to clear up. This cold front is very common in winter in our country. But if the warm air is dry, there may be no rain clouds or high-level clouds in the frontal cloud system. For example, in the high latitudes of northeast and northwest, there is only cirrostratus in front, but snowfall is very common. When warm air convection is unstable, cumulonimbus clouds and cumulonimbus clouds may develop near the front, and thunderstorms may occur, which is more common in summer in China.
② Cold front of the second kind
If it is warm, humid and unstable air, strong cumulonimbus clouds are often formed due to the influence of cold air when the authorities approach the ground front, which is arranged in a long and narrow cumulonimbus belt along the front, and the top often reaches more than 10000. Meters, and the width is only a few tens of kilometers. There is usually a gap in front of this rain belt. When the second cold front comes, it is often storms, dark clouds and lightning. The weather improved soon after the front. This cold front is more common in the second half of our country.
If the warm air is relatively stable, the cloud system of the second cold front is similar to the warm front and belongs to the layered cloud system. Cirrus clouds and cirrostratus were also seen when the front came, and then the clouds gradually became thicker and lower, and sometimes there was precipitation near the front. After the front line passed, the rain disappeared, but the wind speed suddenly increased and a strong wind blew. This cold front usually occurs in winter in our country.
What are the characteristics of "fast forward cold front" and "slow forward cold front"?
In many cases, the change of weather is caused by the influence of "weather system". The main weather systems include frontal system and barometric system. Frontal system includes cold front, warm front and quasi-static front. The pressure system includes low pressure system and pressure system. There are two high-pressure systems.