Kean University Continuing Education

Implementing the Science Standards K-4

Clouds and Cloud Symbols

Introduction

Clouds have been categorized and sorted into various types. Based on cloud properties, the classification system is below is used.

• Layered or Stratiform clouds. Stratiform clouds appear in layers or strata. There are three levels in the troposphere where these types of clouds appear in different forms.
• Stratus clouds form at the lowest levels.
• Altostratus clouds form at the middle levels.
• Cirrostratus clouds form at the highest levels. These have some properties of cirrus clouds and some properties of stratus clouds.
• Puffy or Cumuliform clouds. Cumuliform clouds are the puffy, fair weather clouds that look like big balls of cotton. They also can be found at all three levels of the atmosphere in different forms.
• Cumulus clouds from about 0.5 miles up to about 2 miles.
• Altocumulus clouds can be found in the 2-4 mile range
• Cirrocumulus clouds are found at the highest range.
• Stratocumulus clouds have properties of both stratus and cumulus clouds. They are found in the higher portions of the lowest level.
• Rain clouds. Clouds that produce rain contain the word nimbus in some form.
• Nimbostratus clouds produce rain or snow as a part of general weather systems associated with fronts. When it rains or snows all day as a result of a weather system, it is generally from nimbostratus clouds.
• Cumulonimbus clouds are formed when moist air from the low levels of the atmosphere is carried aloft to the top of the troposphere. This results in thunderstorms which are produced by cumulonimbus clouds. These clouds are associated with strong cold fronts, especially when these fronts are advancing into areas containg warm moist air. This occurs frequently in the southeastern part of the United States in the springtime. Sometimes these clouds are associated with torndoes.

Using symbols to represent current weather and clouds.

When weather conditions are reported on weather maps, a standard form is used. The location of the weather station is represented by a circle and the type of cloud is written above the circle.

The figure above presents two views of the station circle used to report the weather.

(A) A blank weather circle with the wind barb indicated. The three labeled lines indicate the positions where they write the temperature, current weather symbol and cloud type symbol. The inside of the circle indicates cloud cover. The wind barb indicates wind speed and direction.

(B) A sample filled in weather circle. The temperature is 65 degrees and there is fog. The sky is about 4/10 covered with altostratus clouds. The wind is from the northeast at 25.

Meteorologists use other symbols and notations in addition to these. They include indication of dewpoint, barometric pressure, whether the barometric pressure is rising, falling or steady and other important weather information.

The table below lists the symbols and the cloud names used when reporting weather.

Symbol	Cloud Name	Symbol	Cloud Name	Symbol	Cloud Name
	Stratus		Cumulus		Stratocumulus
	Altostratus		Altocumulus		Nimbostratus
	Cirrostratus		Cirrocumulus		Cumulonimbus

The clouds can also be grouped according to their altitude

• High clouds include cirrus, cirrostratus and cirrocumulus
• Middle clouds include altostratus and altocumulus
• Low clouds include cumulus, stratus and stratocumulus

Rain clouds are nimbostratus and cumulonimbus. The nimbostratus clouds are mainly low rain clouds. The cumulonimbus clouds are puffy clouds which start at low levels but make great towers in the sky, often as high as the stratus clouds. These clouds are the ones that produce thunderstorms.

Symbols are used to indicate the amount of cloud coverage at the weather observation station

Symbol	Coverage	Symbol	Coverage	Symbol	Coverage	Symbol	Coverage	Symbol	Coverage
	No clouds		1/4 cover		1/2 cover		3/4 cover		completely overcast
	1/10 cover		4/10 cover		6/10 cover		9/10 cover		sky obscured and not visible