This document discusses different types of pressure systems and fronts that influence weather and climate. It explains that convection causes warm air to rise and cool. Air masses collide to form fronts like cold fronts, where dense cold air displaces warm air causing precipitation, or warm fronts where warm air displaces cold air with light precipitation. It also describes stationary, occluded, and pressure systems, noting that low pressure systems cause air to rise and spiral inward while high pressure systems bring sinking air and fair weather.

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.