Generally, High pressure areas in the atmosphere tend to be clear and Low pressure areas have clouds. Do clouds form in high pressure areas? As the air sinks into the lower part of the atmosphere, the pressure rises, it becomes compressed and warms up, so that no condensation takes place.
Low pressure is what causes active weather. The air is lighter than the surrounding air masses so it rises, causing an unstable environment. Rising air makes the water vapor in the air condense and form clouds and rain for example.
One thought is that the air cools as it rises, and eventually clouds form. Other types of clouds, such as cumulus clouds, form above mountains too as air is warmed at the ground and rises. Clouds also form when air is forced upward at areas of low pressure. Winds meet at the center of the low pressure system and have nowhere to go but up.
Then, how do clouds form over a low pressure center?
The Sun’s (shortwave) radiation mostly goes through the atmosphere, but is absorbed by (and warms) the surface of the seas and land. Warmed air rises vertically (see convection). Winds and Pressure = Loss of air. Winds near the surface as slowed by friction.
Here is what our research found. cumulus clouds can form in high pressure., and sometimes yes. High pressure is characterised by descending air which warms as it descends, which is unfavourable for cloud formation, hence much of the time, high pressure is associated with clear skies.
How do clouds dissipate?
If clouds form when water vapor cools and condenses, it only makes sense that they dissipate when the opposite happens—that is, when the air warms and evaporates. How does this happen? Because the atmosphere is always in motion, drier air follows behind the rising air so that both condensation and evaporation continually occur.
This of course begs the question “Why doesn’t cool air form clouds when it cools?”
Cool air can’t hold as much water vapor as warm air, so when its temperature cools down to the dew point temperature, the water vapor inside of the parcel becomes saturated (its relative humidity equals 100%) and condenses into droplets of liquid water. But by themselves, water molecules are too small to stick together and form cloud droplets.
How do clouds grow?
But in order to grow a cloud, we need to get the water vapor from a gas to its liquid form. Clouds begin to form when a parcel of air rises from the surface up into the atmosphere. (Air does this in a number of ways, including being lifted up mountainsides, lifted up weather fronts, and being pushed together by converging air masses .).
The type of cloud and altitude (low, middle, or high) it forms at is determined by the level where an air parcel becomes saturated. This level changes based on things like temperature, dew point temperature, and how fast or slow the parcel cools with increasing elevation, known as “lapse rate.”.