1. Pressure Systems

2. Different Temperatures - Different Pressures
Less
Dense
Pressure
Cool
Air
Denser
More
Pressure
Warm
Air

3. Air Pressure
Is the amount of weight the atmosphere put on the surface of earth at a certain time

4. Air pressure tool
Barometers measures air pressure in millibars (mb)

5. HIGH pressure H
Means that the air molecules are close together and are putting a lot of pressure on earth’s surface. This pushes all clouds and precipitation away from an area.

6. High Pressure Brings clear skies and no precipitation.
Air moves down and clockwise

8. LOW pressure L
Means that the air molecules are NOT pushed together tightly and not a lot of pressure is being put on the surface of the earth. This lets clouds and precipitation in an area.

9. LOW PRESSURE Brings wind, clouds and usually bad weather to an area.
Air moves up and counterclockwise.

10. Wind movement Surface winds move out and clockwise
Surface winds move in and counterclockwise

12. Map practice #1
Wisconsin
Boston
Texas

13. Do now: Weather looks like this: Molecules Weather looks like this:
High Pressure
What do the molecules look like? What kind of weather does it create? Diagram below:
   
Low Pressure
What do the molecules look like? What kind of weather does it create? Diagram below:
The type of weather high pressure brings is:______________________________________________________________________________________________________________________________
The type of weather low pressure brings is:________________________________________________________________________________________________________________________________________
Weather looks like this:
Molecules
Weather looks like this:
Molecules

14. Part 2: Map practice #2
Wisconsin
Boston

15. Do now: Compare and contrast high and low pressure systems

16. Compare/Contrast Chart High and Low Pressure
High Pressure
Low Pressure
Type of phenomenon
Weather system
Determined by…
Changes in air pressure
Density of air
Higher
Lower
Representation on a map
H (typically blue)
L (typically red)
Motion of air
Clockwise, air sinks
Counterclockwise, air rises
Weather
Clear skies, no precipitation
Wind, clouds, severe weather

17. Part 4: Map practice #4

18. Low vs. High

19. Pressure Gradient Force

20. How is pressure measured?
Isobars- lines of equal atmospheric pressure drawn on a meteorological map.
Isobar lines may never cross or touch.
Isobar lines may only pass through pressures of or - 4. In other words, allowable lines are 992, 996, 1000, 1004, 1008, and so on.
The atmospheric pressure is given in millibars (mb).

22. Winds Horizontal movements at surface
Names from WHERE it came from…not where it is going!!!

24. Wind Systems
Air flows from areas of HIGH pressure to areas of LOW pressure creating wind.