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nick101 created the topic: Conditional Instability
Doing the CMET practice exam I came across this question "One of the prerequisites for the formation of a thunderstorm is -"
In the answer it states the following:
The conditions necessary for the formation of a thunderstorm are:
1. Conditionally stable atmosphere.
2. High humidity.
3. A trigger mechanism to begin the initial lifting of the air.
Conditional stability exists when dry air is stable but saturated air is unstable. That is, rising air that doesn't form cloud will eventually stop rising and cause no real problems for a pilot. However, once cloud begins to form, the cloud will become unstable and rapidly grow to form a large cumulonimbus cloud.
The correct answer is: a conditionally stable atmosphere
My understanding is that you need a conditionally unstable atmosphere " a deep layer of conditionally unstable air above the LFC which allows the parcel of saturated air to continue to rise to a considerable height, i.e. to the -20°C level and beyond'