Why is Jianghuai a quasi-static front in summer and Kunming a quasi-static front in winter?

Quasi-static frontal weather is generally divided into two types: one is the development of cloud system on the front with obvious precipitation. For example, the quasi-static front in South China mostly evolved from the weakening of the cold air mass and the strengthening of the warm air mass during the southward movement of the cold front, so the weather is similar to the first kind of cold front, except that the front slope is smaller, the cloud and rain area is wider, and the precipitation area is not limited to Feng Yu area, but can be extended to a larger area behind the front, with less precipitation intensity and continuous precipitation. Because the quasi-static front moves slowly and often swings back and forth, the rainy weather lasts for 10 days to half a month, or even more than a month. "It rains in succession during the Qingming Festival" is a portrayal of this kind of weather in the south of the Yangtze River. In early summer, if the humidity of the warm air mass increases and the lower layer heats up, the gas layer may be unstable, and cumulonimbus clouds and thunderstorms may also form on the front. The other is the development of the main cloud system under the front, and the quasi-static front without obvious precipitation. For example, the quasi-static front in Kunming is quasi-static because the cold air in the south is blocked by mountains, and the warm air on the front is dry and slowly rising, which can not produce a large range of cloud systems and precipitation. The cold air mass under the front contains more water vapor and rises along the hillside. Coupled with turbulence and mixing, it is easy to form stratocumulus clouds or thick nimbostratus, often accompanied by continuous precipitation. This quasi-static front mainly appears in South China, Southwest China and the north side of Tianshan Mountain, and the winter lasts for half a year, which has a great influence on the weather in these areas and their vicinity.