1. Precipitation, moisture & clouds

2. 3 ways precipitation can form

3. 1. Orographic precipitation
This occurs when an air mass forced to rise over a mountain range.
The air becomes cooled and precipitation takes place.

4. 2. Convectional precipitation
This is brought about by rising and abrupt cooling of air that has been warmed by the extreme heat of the ground surface.
The water vapour carried by the air condenses, producing heavy rain.
Convectional rainfall is usually accompanied by a thunderstorm.

5. 3. Cyclonic (frontal) precipitation
This takes place at the boundary, or front, between a mass of warm air from the tropics and a mass of cold air from the poles.
The water vapour in the warm air is chilled as it is pushed over the cold air and condenses to form clouds and rain.

6. What is a cloud?
: A visible mass of condensed water droplets or ice suspended in the atmosphere

7. 4 main types of cloud by shape

8. 1. cumulus
Latin for 'heap', to describe a puffy cloud

9. 2. Cirrus
Latin for 'curl of hair', to describe a wispy cloud

10. 3. Stratus
Latin for 'layer', to describe a sheet-like cloud

11. 4. Nimbus
Latin for 'rain', to describe a rain cloud.

12. Then you divide the clouds by their height in the atmosphere
Name
Height
Composition
Examples
High
Above 6 km
Ice crystals
Cirrus, cirrostratus
Middle
2-6 km
Water droplets
Altocumulus, altostratus
Low
Within 2 km
Nimbostratus, stratocumulus
Vertical Development
Variable
Cumulonimbus

13. A few more terms to know

14. Wind Chill
: It shows us how much colder the wind makes our skin feel.
The temperature we feel is not the air temperature but our skin temperature.
A person will sense that it's colder because the wind steals body heat by blowing away warm air that surrounds the skin.

15. Heat index
: A measure that combines air temperature and humidity to show how hot it feels

16. What is the difference between…?
Blizzard: a severe storm that lasts 3 or more hours, and brings low temperatures, strong winds and poor visibility due to blowing snow.
Squall: a strong, sudden wind which generally lasts a few minutes then quickly decreases in speed.
Flurry: a snowfall that suddenly stops and starts and changes rapidly in intensity; the accumulation and extent of the snow are limited.

17. humidity
Absolute humidity: the actual amount of water vapor in the air.
Relative humidity: how much water vapor there could be in the air at its current temperature.
Warm air can hold more water vapor than cold air.