Why does the weather change dramatically near the front?

Front refers to a long strip area formed when cold and warm air meet, which is hundreds to thousands of kilometers long. Fronts are divided into warm front, cold front, quasi-stationary peak and occluded front. Most of what you said belongs to the cold front.

The cold air mass behind the cold front is powerful and moving fast, which violently impacts the warm air, making the warm air rise rapidly, forming a narrow range of cumulus clouds arranged along the front, resulting in convective precipitation weather. In summer, the air is heated unevenly and has strong convection. When the cold front moves, there are often strong winds, dark clouds, heavy rains and lightning, and the meteorological elements change dramatically. However, this kind of weather lasted for a short time. After reaching the front line, the temperature dropped sharply and the weather suddenly became sunny.