Wall clouds are lower because they form when rain-cooled air is drawn upward into the storm's updraft.
Here's a breakdown:
Wall clouds represent a lowering of the cloud base. According to research, wall clouds likely develop when rain-cooled air is pulled upward along with warmer, buoyant air as the strengthening updraft tries to replace increasing volumes of rising air.
Essentially, the process works like this:
- Rain-Cooled Air: As rain falls within a thunderstorm, it cools the air around it. This air becomes denser.
- Uplift: A strong updraft, which is a rising current of air, is a key feature of severe thunderstorms.
- Interaction: The updraft pulls some of this rain-cooled air upward, alongside the warmer, more buoyant air already rising.
- Condensation: As the rain-cooled air rises, it mixes with the warmer, moist air in the updraft. This can lead to condensation at a lower altitude than the general cloud base.
| Factor | Explanation |
|---|---|
| Rain-Cooled Air | Rain falling through the air cools it, making it denser. |
| Updraft | Severe thunderstorms have strong updrafts: rising currents of air. |
| Mixing | The updraft pulls the rain-cooled air upward alongside the warmer, buoyant air. This mixing is crucial. |
| Condensation | As the rain-cooled air rises and mixes, condensation can occur at a lower altitude than the general cloud base due to the change in temperature and humidity, leading to the formation of a wall cloud. The rising, rotating column of humid air cools as it ascends, causing water vapor to condense and form the wall cloud. |
