1. Clouds and Precipitation

2. Clouds Form as warm air is forced upward, expands, and cools.
Billions of tiny droplets of water and dust form a cloud.
3 main types of clouds: Stratus, Cumulus, and Cirrus

3. Stratus Forms at low altitudes
Clouds of flat layers, or smooth, even sheets
Stratus clouds near the ground are called FOG
Associated with fair weather, rain or snow

4. Cumulus
Clouds are large, puffy, white clouds, often flat bases and may have gray centers.
They grow upwards and tall
Associated with fair weather, snow or thunderstorms

5. Nimbo or Nimbus Any cloud that produces precipitation.
Cumulonimbus “thunderheads” produce thunderstorms.

6. Cirrus Cirrus clouds are the highest clouds.
They usually mean fair weather.
They look white and feathery.

7. Precipitation Water falling from the clouds
4 different forms: Rain, Snow, Sleet and Hail
Air temperature determines which it will be

8. Rain Rain is when liquid water falls from the clouds
Rain will fall when temperatures are above freezing.

9. Snow
Snow forms when the temperatures are so cold that water vapor turns into a solid.

10. Sleet
Sleet forms when raindrops pass through a layer of freezing air near the surface.

11. Hail Hailstones are pellets of ice that form inside a cloud
Melt once they hit Earth’s warm surface