ATMO 336 Lecture Notes - Lecture 7: Cumulonimbus Cloud, Thunderstorm, Dew Point
8 Oct 2016
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Document Summary
Clouds typically form where air is rising upward in the atmosphere. Thunderstorms, tornadoes, and hurricanes form when the atmosphere is unstable. The more unstable the atmosphere, the higher the potential for severe weather. There are two general types of clouds: stratiform-type clouds. Vertically thin layers of cloud that often cover large horizontal areas. Tend to form in stable environmental conditions: cumuliform-type clouds. Vertically tall clouds, but horizontally not that large, often see clear sky between cloud elements. The atmosphere becomes unstable when the temperature of a lifted parcel is warmer than the surrounding air. A lifted parcel accelerates upward because it has become less dense than the surrounding atmosphere. Meteorologists use a similar method to assess the potential for thunderstorms and severe weather. The more unstable the atmosphere, the greater the potential for violent storms. The greater the positive difference between the parcel temperature and the surrounding air temperature, the more unstable the atmosphere.
