Clouds!!!

Rachel and Mariah

How do clouds form

• Clouds form when warm air raises and cools. The left over water vapor then has no where to go so it becomes cloud droplets and forms a cloud. The cloud either re-evaporates or forms precipitation.

• There are three things need for a cloud to form:– Water Vapor– Dust Particles– Temperature or Pressure Change

Lower Level Clouds

Cumulus : are cauliflower-shaped low level clouds with dark bases and bright tops. When observing cumulus, you are actually observing the condensation process of rising thermals or air bubbles at a certain level in the atmosphere known as the condensation level.

Stratocumulus

are low clouds that generally move faster than cumulus. They tend to spread more horizontally rather than vertically. Like cumulus, the bases of stratocumulus are normally darker than the tops.

Stratus Defined as low cloud that appears fragmented and thin. It can also occur in

the form of a layer or sheet. The sun, moon and generally the sky can usually be observed through stratus clouds. Stratus lacks the vertical growth of cumulus and stratocumulus, and therefore lacks the contrast.

Medium Level Clouds

• Altocumulus : As the name suggests, altocumulus refers to the middle level cloud that exhibit to some extent the features normally associated with cumulus. This includes cumuliform tops and bases that are usually relatively darker than the tops.

Altostratus

• Altostratus refers to middle level cloud that appears as a flat, smooth dark grey sheet. These clouds are most often observed as large sheets rather than isolated areas. However, in the process of development, altostratus may develop in smaller filaments and rapidly develop to larger sheets.

Nimbostratus

• Nimbostratus can be described as a widespread light grey or white sheet of cloud that produces persistent rain or showers. Because of its light colors, nimbostratus lacks contrast and in fact is quite difficult to photograph.

High Level Clouds

• Cirrus : Cirrus clouds are higher level clouds that develop in filaments or patches. They are virtually brilliant white attributed to their ice crystal composition. They occur in flat sheets with a low height to base ratio and are usually isolated with large breaks of sky.

Cirrostratus

• Cirrostratus represent clouds that are more widespread than cirrus but containing some similar features. Like cirrus, they are brilliant white and lack in contrast. Sunlight can pass through cirrostratus but this again depends on the varying thickness of the clouds.

Cirrocumulus

• Cirrocumulus is a higher level cloud that is brilliant white but with a spotty appearance created by the many small turrets. The turrets indicate vertical turbulence within the cloud. Despite this spotty appearance, cirrocumulus contains many features associated with a cirrostratus cloud.

The cumulonimbus cloud

• Cumulonimbus clouds, which are normally associated with thunderstorms, consist of a combination from some or all of the cloud groups. The heights of cumulonimbus clouds vary depending on the conditions but are typically of the order of tens of kilometers from the base to the cloud tops.

Cloud Symbols

Clear Slightly Scattered Cloudy Overcast Broken Scattered

Mists, fogbanks or low clouds