Before the thunderstorm in summer, the weather was sultry. What is the reason?

This is because there are two conditions for the occurrence of thunderstorms: first, the ground temperature should be high; Second, the atmospheric humidity should be high. When the ground temperature is high, the air temperature near the ground can rise very high, and when the temperature rises, it will gently float to the high altitude; If it is only hot, but the air is dry, the thunderstorm will not happen. When humid air rises to the sky, Lei Yun will form. When there are thunderclouds in the sky, there may be thunderstorms.

The weather is hot, there is a lot of water vapor in the air, and the sweat on our bodies is not easy to disperse, so we will feel bored. It's like taking a bath in the bathroom, and it feels stuffy. This property is caused by the high temperature and a lot of steam in the bathroom. So sultry is a sign of high atmospheric temperature and more water vapor, and it is also a sign of lightning. But sometimes, although it's sultry here, there can't be a thunderstorm. This is because the scope of thunderstorms in summer is small, and thunderstorms fall elsewhere instead of on us. After summer, the weather is getting cooler and cooler. After the heavy rain in summer, the temperature plummeted, but it was still very hot before the thunderstorm. Why?

Summer is the most common season for thunderstorm weather. In this season, the sun faces the northern hemisphere and the temperature is higher. Direct sunlight makes the water on the ground evaporate faster than in other seasons. Because of the high temperature, the air near the ground can hold more water vapor. If there is no wind, the air near the ground will be saturated with water vapor, and the air can no longer contain water vapor, so the water on the ground will not continue to evaporate. On a windless and sultry summer day, the air still flows. With the increase of temperature, water vapor increases, which makes the air density decrease and become "lighter", and the lighter air keeps rising. However, the temperature in high places is low, the air is cold, and the lighter wet and warm air gradually decreases during the temperature rise. As the air cools, water vapor cannot be completely contained, and some of it will condense to form water droplets.

In the hot summer afternoon, the air rising on the ground is strong, and the water droplets in the sky are too small to fall immediately and be pushed onto it. Hot and humid air rises, forming huge and expanding cumulonimbus clouds. As the water droplets in the clouds get bigger and bigger, they begin to fall and form rain. At this time, there will be a downward airflow to bring down the cold air at high altitude, so before the thunderstorm comes, you will often feel the cool wind, which means that a thunderstorm is coming.

Since it is a thunderstorm, how did the thunder come from? Compared with circulating air, the temperature in the lower part of cumulonimbus cloud is higher and the temperature in the upper part is lower, and there are strong updraft and downdraft in the cloud. A large number of water vapor condensates in cumulonimbus clouds, such as water droplets, supercooled water droplets, ice crystals, graupel (opaque snow beads), hail, etc., generate electric energy in the cloud through many complicated processes such as freezing, collision, extrusion, melting, etc., separate positive and negative charges, and form positive and negative charge centers in the cloud. When the collected amount of electricity is large enough, a breakdown discharge will occur between the opposite charge centers, resulting in a spark discharge and a strong sound, which is lightning.