1. Weather: Maps, Symbols, and Basic Concepts

2. Without a knowledge of weather basics, we must depend on the…professionals.
Sometimes the weather is just CRAZY!

3. Which is heavier? HIGH PRESSURE LOW PRESSURE
Contains mostly dry air Contains more moisture
Nitrogen Mass = 14 units Hydrogen Mass = 1 unit
Oxygen Mass = 16 units ( X 2 = 2 units)
Oxygen Mass = 16 units
TOTAL MASS = 30 units TOTAL MASS = 18 units
So, drier air is nearly twice as “heavy” as air in which the nitrogen and oxygen has been replaced with water molecules. This is why “fair weather” is associated with HIGH PRESSURE and rainy weather is associated with LOW PRESSURE.

4. High and Low Pressure Areas
High pressure causes air to sink; rotates clockwise
Usually results in several days of clear sunny skies
Air rises; forms clouds; rotates couterclockwise
Usually results in rain and storms

5. Types of Clouds

6. Air masses are like people…
…they take on the characteristics associated with their surroundings.

7. Tornado Alley

8. Fronts
A front is the boundary separating air masses of different densities
Fronts extend both vertically and horizontally in the atmosphere

9. Fronts: Five Types of Fronts
1. Cold Front: The zone where cold air is replacing warmer air
In U.S., cold fronts usually move from northwest to southeast
Air gets drier after a cold front moves through

10. Fronts: Five Types of Fronts
2. Warm Front: The zone where warm air is replacing colder air
In U.S., warm fronts usually move from southwest to northeast
Air gets more humid after a warm front moves through

11. Fronts: Five Types of Fronts
3. Stationary Front: When either a cold or warm front stops moving
When the front starts moving again it returns to either being a cold or warm front

12. Fronts: Five Types of Fronts
4. Occluded Front: Formed when a cold front overtakes a warm front
This occurrence usually results in storms over an area
In U.S., the colder air usually lies to the west

13. Fronts: Five Types of Fronts
5. Dry Line (Dew Point Front): Boundary separating a dry air mass from a moist air mass
This occurrence can result in tornadoes being formed
Usually found in western part of U.S.

14. Isotherms
Lines on a weather map that connect places of equal temperature

15. The Doppler Effect

16. What does it mean?
The Doppler Effect, or Doppler shift, is the apparent change in the frequency of a wave caused by the fact that the source is moving TOWARD or AWAY from the detector

17. The disadvantage of the Doppler Effect….

18. How you get busted….

19. How it works with weather:

20. Typical Doppler Radar tower….

21. Sample images…
“Hook echo”