Weather Front

An air mass is a body of air with the same temperature and moisture throughout 

Air masses that come from tropical places will be warm

Air masses that come from polar places will be cool

Air masses that originate from the ocean will contain a lot of moisture

A moving mass of cold air

When cold air mass and warm mass collide...cold air slides under the warm air pushing it up 

As the cold air moves away, the warm air replaces it

Since warm air is less dense, it rises above the cold air

Warm fronts move slowly, so rainy weather usually stays around for days

A stationary front forms when a cold front or warm front stops moving.

this happens when two masses of air are pushing against each other but neither is powerful enough to move the other.

Water vapor condenses into rain, snow, fog, or clouds.

A stationary front may stay put for days.

The occluded fronts are a result of three air masses coming in contact with one another.

The third air mass can be lifted up and trapped or sandwiched between the first two air masses