Title: Air Masses and Fronts
1Air Masses and Fronts
Warm Up What type of rock is formed from
cooling lava?
2? Air Mass VIDEO Clip ?
3Air Masses
- Air masses have the same properties as the
surface over which it develops - Maritime Wet
- Continental Dry
- Polar Cold
- Tropical Warm
mP wet/cold cP dry/cold mT wet/warm cT
dry/warm
4Air Masses in North America
5Fronts
- A front is the boundary where two air masses
meet. - Types of fronts
- Warm Front
- Cold Front
- Occluded Front
- Stationary Front
6Front VIDEO Clip ?
7Cold Front
- Cold dense air pushes under a warm air mass.
- The cold dense air moves faster and causes the
warm air rises quickly. - Narrow bands of violent storms form.
8Why do cold fronts bring heavy rain and storms?
- Cold air interacting with warm air a sudden
drop in temperature CONDENSATION occurs quickly
and a fast difference in pressure - Creates cumulonimbus clouds
- Cold dense fast moving air high winds
What you see in a weather map!
9Cold Front Video Clip
10Warm Front
- Warm air slides over departing cold air.
- Large bands of precipitation form
11Why do warm fronts bring mild weather?
- Its more difficult for the warm air to move
against the cold dense air so there is a gradual
difference in pressure and temperature
What you see in a weather map!
12Warm Front Video Clip
13Occluded Front
- Two cold air masses merge and force warm air
between them to rise quickly. - Strong winds and heavy precipitation will occur.
14Why do occluded fronts bring heavy rain and
storms?
- Cold air that is more dense moves into an area of
low pressure CONDENSATION occurs quickly - Forms cumulonimbus and nimbostratus clouds
What you see in a weather map!
15Stationary Front
- Warm and/or cold front stops moving.
- Light wind and precipitation may occur across the
front boundary.
16Why do stationary fronts bring long light
precipitation?
- Neither front is strong enough to move the other
- Can stay put for days
- Differences in temperature rain or snow
What you see in a weather map!
17Cyclones and Anticyclones
- Areas of HIGH and LOW pressure
- Cyclone LOW PRESSURE spin counterclockwise
associated with storms and precipitation - Anticyclone HIGH PRESSURE spin clockwise
associated with fair weather.
18Cyclones and Anticyclones in the USA
19Cyclone Video Clip ?