ATSC 113 Weather for Sailing, Flying & Snow Sports
Clouds
Learning Goal 1a. Identify & classify clouds, and relate them to local and larger-scale weather systems and to potential hazards to aircraft.
We can divide clouds into "normal" clouds and "special" clouds. Here, we explore normal clouds. Special clouds are covered in Learning Goal 1b.
Normal clouds are classified into two categories (click on these links for more photos):
- Convective
clouds or cumuliform
clouds (Cu) look like stacks of cotton balls, and are
associated with updrafts.
- Layer clouds or stratiform clouds (St) look like sheets or blankets that can extend hundreds of kilometers horizontally.
The table below compares cumuliform and stratiform clouds (z = height above ground). For more info and cloud photos for each of these categories, click on the links above.
Clouds |
Sketch of different types of this cloud |
Sample photo |
| Cumuliform |  |
 |
| Stratiform |  |
 |
Stratocumulus
are a low-altitude layer of lumpy clouds. They don't fit well in
the normal cumuliform or stratiform groups, yet they have
characteristics of both groups. There are many photos of
stratocumulus clouds in Learning Goal 1c on cloud-coverage, but here is
a good photo and the associated video.
| Stratocumulus (rooftop video) |
 |
For more photos of the main types of stratiform and cumuliform
clouds, see
https://www.weather.gov/jetstream/clouds_intro
And the basic cloud types as viewed from aircraft:
https://cloudatlas.wmo.int/observation-of-clouds-from-aircraft-descriptions.html
Key words: convective clouds, cumuliform clouds, layer clouds, stratiform clouds, stratocumulus
Extra info for experts; Not Needed for this Course.
Use this expert_resources link to find all the items listed below:
- Item - Topic
- World.A.1. - World Meteorological Organization (WMO) "International Cloud Atlas"
- USA.B.1. - Wikipedia list of cloud types
- World.A.2. - WMO: Manual on Cloud Observations (an old, outdated document)
- USA.A.1. - American Meteorological Society (AMS): Glossary of Meteorology
- USA.C.1. - Practical Meteorology (PrMet): Chapter 6, Clouds
Image credits. All figures by Roland Stull.