Predicting the Weather with Clouds
From the shape, the movement and the height of clouds one can get interesting information on how the weather could change. Here are just a view tips:
By watching the movement of CIRRUS (high clouds) and the direction in which the streaks are pointed, you can get a sense of which direction the weather front is moving. Link image cirrus
ALTOCUMULUS are grayish-white clouds blanketing the entire sky. They tend to look like large fluffy sheets in which there is a lot of contrast between light and dark. Sun does not pass through them. If you see them in the morning, prepare for a thunderstorm in the afternoon. Link image Altocumulus
Low clouds (eg. STRATUS) tend to contain water, but can also be comprised of snow if the weather gets cold enough they block sunlight and can bring precipitation and wind. Link image stratus
CUMULUS CLOUDS are your stereotypical white «cotton ball» clouds. As long as the clouds remain low clumps floating across the sky, there will be fair weather. However, you need to keep an eye on these clouds because any vertical growth can indicate the start of a large storm. Link image cumulus
CUMULONIMBUS are cumulus clowds that have grown vertically into an anvil-like shape. The anvil tends to point in the direction the storm is moving. These clouds bring most dangerous weather such as rain, lightning, hail and tornadoes.
More detailled information :
Wikehow «How to forecast the weather using clouds»