1. Fronts and Pressure System
Notes of Doom!

2. Remember what drives our
climate/weather forces!

3. Another Example of ConvectionAnother Example of Convection
Convection is heat energy moving as aConvection is heat energy moving as a fluidfluid fromfrom hotter tohotter to
coolercooler areasareas..
Warm air at the ground surface rises as a thermal bubbleWarm air at the ground surface rises as a thermal bubble
expands, consumes energy, and hence cools.expands, consumes energy, and hence cools.

4. Fronts
• Air masses are large pockets/blobs of air
that move over land
• When 2 air masses collide its called front.
• Fronts- are narrow regions between 2 air
masses of different densities.
• Density of air masses depend on
temperature, pressure, and humidity of air

5. Cold Front
• Cold, dense air displaces the less dense
warm air.
• Precipitation and T-storms are common

6. Warm Front
• Warm air displaces cold air
• Light precipitation common along warm
fronts.

7. Stationary Front
• 2 air masses meet but do not advance
• Frequently occur when both air masses have small
temperature and pressure gradients between them.
• Light winds and light precipitation

8. Occluded Front
• Cold air moves so fast that it overtakes a warm front and pushes the
warm air upwards.
• Cold air from behind warm front will meet up with cold air in front of
warm front.
• Strong winds and heavy precipitation common along occluded
fronts.

9. Pressure System
• Air will either rise or sink near the Earth’s
surface.
• Air always from an area of high pressure
to an area of low pressure.
• Sinking or rising air with the Coriolis effect,
results in rotating high and low pressure
systems. (Air moves in a circular motion)

10. Low-pressure system
• Air rises and air coming in from outside spirals inward towards the
center. Then it continues up.
• Spiraling air is due to coriolis effect
• Air rises, cools, and condenses into clouds and precipitation
(usually)

11. High-pressure system
• Sinking air moves away from the center when it reaches the Earth’s
surface.
• High pressure systems are usually associated with fair weather.