1. Precipitation and fronts
Coulter

2. Air mass
Body of air that has similar temperature, humidity, and air pressure at any given height is called an air mass.
Four major types of air masses influence the weather in North America: maritime tropical, continental tropical, maritime polar, and continental polar.
Tropical: warm
Polar: cold
Maritime: form over oceans
Continental: form over land

3. Maritime tropical Warm, humid air masses form over tropical oceans.
Form over the gulf of Mexico and Atlantic ocean. They move over the southeastern U.S. they influence weather in the central and eastern U.S.
Form over the Pacific ocean, they mainly influence the weather on the west coast.
In the summer they bring hot, humid weather
In the winter they bring rain and snow

4. Maritime polar
Cool, humid air masses form over the North Pacific and North Atlantic oceans.
They affect the west coast more than the east.

5. Continental tropical
Hot, dry air masses form mostly in the summer over dry areas of the Southwest and northern Mexico.
Typically smaller air masses

6. Continental polar Large air masses form over Canada and Alaska.
Bring bitterly cold weather with low humidity.
Bring clear, cold, dry air to much of North America

7. Types of fronts Four types of fronts: Cold fronts Warm fronts
Stationary fronts
Occluded fronts

8. Cold fronts Tend to move quickly and cause abrupt weather changes.
After a cold front passes through an area, colder, drier air moves in often bringing clear skies, a shift in wind, and lower temperatures.
STORY TIME:
Cold front is like the big brother and warm from is the little brother. Cold front wants to get into the fridge and warm front is in the way, so cold front picks up and throws warm front over his head. Warm front cries (rains) all over cold front. THE END!

9. Warm fronts Fast-moving warm air overtakes slow-moving cold air.
Cold is more dense so warm moves over the cold air.
After a warm front passes through an area, the weather is likely to be warm and humid.
STORY TIME:
Warm front is back, he is angry, and is ready to take on cold front again. This time will be different! Warm front gets as much distance as possible, runs as fast as he can toward cold front. Cold front being the BEST big brother ever, pretends that warm front is moving him. Warm front is going so fast that he ends up flying over cold fronts shoulders. Tears are still falling, poor warm front. Cold front keeps walking, leaving behind the crying warm front. Maybe not the BEST big brother. THE END!

10. Stationary fronts
Cold and warm masses meet, neither one can move the other.
They face in a standoff. If it is stalled in an area, it may bring many days of clouds and precipitation
STORY TIME:
They meet again! What is going to happen? Plot twist! They are the same size…
Warm front grew up a bit and confronts cold front about all his horrible behavior in their past. Cold front is not scared of “whittle warm front!” The confrontation can go one of two ways, warm front can scream and cry, lets face it, this is probably what will happen (rain, thunder, and lightning) or warm front can throw his “whittle fist” and start a fight (tornado). Cold front will not back down in either situation. He is strong and doesn’t cry. THE END

11. Occluded front Warm air mass is caught between two cold air masses.
Warm air is cut off from the ground.
Warm air will cool and its water vapor condenses. Weather may turn cloudy and rain may fall
STORY TIME:
Cold front has a friend! What will warm front do? There are two! The two cold fronts pick up warm front, who is screaming, “put me down!” The cold fronts laugh and laugh, but never put warm front down. Warm front does not cry this time, he is a big kid now after all. Instead he gets revenge! Warm front PEES on their head. Warm front WINS! THE END