1. A large body of air with similar temperature, humidity, and air pressure.
Air masses form over large land or water masses.
Air Mass
Two Properties of air masses are:
Moisture content
Temperature
MAP TAP
Weather Fronts

2. 4 Types of Air Masses Tropical Polar Maritime Continental
Near the equator
Accompanied by warm air
Polar
Far from the equator
Accompanied by cool air
Maritime
Over water
Accompanied by moist air
Continental
Over land
Accompanied by dry air

3. Air Masses Meet
When 2 air masses meet, they do not mix. What happens is that they form a border that is known as a front. Most of the weather that we think of happens along fronts. Where air masses meet but do not mix due to different temperatures and densities they becomes a front.

4. Cold Fronts
A cold front forms when a cold air mass catches up to a warm air mass.
Colder air forces the warm air higher into the atmosphere.
This warm air that is pushed up cools and forms clouds. This reaction causes rain to develop and thunderstorms also occur along a cold front.

6. A warm front is when a warm air mass catches up to a cold air mass
A warm front is when a warm air mass catches up to a cold air mass. ( Just the opposite of a cold front.)
Warm Fronts
Warm air slides over the cold, dense air. This also causes clouds to form, but many miles ahead of the front. As the front approaches and passes it can cause steady rain or snow to fall. After all of this happens, the sky becomes clear (without clouds) and this is also when the temperature starts to rise (get higher).

8. Stationary Front
This front is created when a cold air mass and warm air mass collide and do not mix. This collision could cause constant snow or rain for days. This type of front can stay in the same place for days.
When this front stays in the same place for a long time there is constant snow or rainfall and this leads to several inches of snow or it could even cause a flood.

9. Stationary Fronts A front that stops moving or is moving very slowly.
Shown on a weather map with alternating red semicircles pointing away from the warm air and blue triangles pointing away from the cold air.
MAP TAP

10. Occluded Fronts When a warm front is trapped by 2 cold fronts.
Shown on a weather map by a purple line with alternating triangles and semicircles pointing the direction the front is moving.
Brings Strong WINDS and HEAVY Precipitation.
MAP TAP
Weather Fronts