1. Precipitation

2. Facts about air we need to know
Warm air is lighter than cold air
Warm air holds more moisture than cold air
Water holds heat longer than land
Air cools as it rises
When air passes over water, it picks up moisture

3. Reasons why air may rise
It is forced up by relief (mountains)
It absorbs heat from the earth’s surface
It is pushed up by a cooler denser (heavier) air mass

4. Air Pressure Air has weight = air pressure Low Pressure High Pressure
Warm air rising
Bad weather
High Pressure
Cold air falls towards the earth
Good Weather
When a pressure goes from High to Low = STORM

5. Types of Precipitation
1. Relief (Mountain)
2. Frontal (Battle of the sky)

6. Relief Precipitation Warm ocean air gains moisture
Warm air is forced to rise over the hill
Air cools and condenses to form clouds = Precipitation
Air sinks and is warmed so it can hold more moisture and less rain.

7. Frontal Precipitation (aka Battle of the sky)
Cold, dense (heavy) air mass hits less dense, warm moist air, forcing it up
As air mass rises, it cools. Condenses to form clouds and precipitation.
Moisture falls through cold air below to cool the earth’s surface.