There are two main ways that a cloud is formed. Rising air currents form the first type, cumulus clouds, giving a heaped-up appearance. The second type, stratus, forms when a layer of air is cooled below its saturation (dew) point, which makes the cloud look like a blanket of fog.
To understand the daily weather, you should know what some of the basic clouds types are and what kind of weather they usually bring. Note that Cirro/Cirrus are high-altitude clouds, while alto are mid-range clouds.
|Stratus: low-altitude, densely foggy clouds that can result in a light drizzle of rain or an overcast sky.|
|Nimbostratus: rain and snow clouds. These are low-lying clouds that are distinguished by their darker color; they also often have visible sheets of rain that extend from them. ‘Nimbus’ means rain cloud. (Cumulonimbus clouds are thunderclouds.)
Stratocumulus: sheets of gray, puffy clouds that usually foretell bad weather.
|Cirrus: high-altitude ice clouds (formed by ice crystals instead of water droplets) that appear as wisps. These often mean good weather for the immediate future.|
|Cirrocumulus: high-altitude ice clouds. They look similar to lower altocumulus clouds: although they are in denser sheets and often have a lighter color, they have the same fish-scale or ripple look as altocumulus. They usually foretell precipitation and thunderstorms.|
Barometric pressure is another way to forecast approaching weather. A low barometric pressure or falling barometric pressure shows a change in atmosphere that usually means a storm is coming.
A Cloud Chart is an excellent tool to learn to forecast the weather from observing the clouds. We sell a full-color chart that includes 35 cloud pictures with a description of the weather that is associated with each one.
Cloud pictures are the property of Cloud Chart, Inc. and are used with permission.