1. Weather

2. What is weather?
Refers to the state of the atmosphere at a specific time and place.
Weather has several components…

3. Air Temperature
the measure of the average amount of motion in particles

4. Wind a natural movement of air of any velocity
especially : the earth's air or the gas surrounding a planet in natural motion horizontally

5. Humidity The amount of water vapor present in the air
Relative Humidity -is a measure of the amount of water vapor present in the air compared to the amount needed for saturation at a specific temperature

6. Precipitation Water that falls from the clouds
Air temperature determines the form of precipitation that falls
5 main types of Precipitation: Rain, Sleet, Snow, Freezing Rain, and Hail

7. Types of Precipitation
Rain
Sleet
Snow
Hail

8. Air Masses
A large body of air that has properties similar to the part of the Earth’s surface over which it develops.

10. Air Mass Map

11. Air Pressure Warm air = expanding or rising air
leaves behind Low (L) pressure
Cold Air = sinking air
leaves an area of High (H) pressure

12. Reading a Weather Map…

13. Reading a Weather Map… bars-connect points of the “same”
Examples: temperature and wind speed
The further away the lines the lower the wind speed

14. Isobars connects areas of equal pressure
BAR comes from BARometric pressure

15. Isotherms Connects areas of equal temperature
“therm” means temperature

16. Weather Station Model (not seen on the TV)
Air pressure – the pressure that an air mass exerts on the Earth
Temperature – measure of the heat or cold for an air mass; measured in ° Fahrenheit or ° Celsius

17. Weather Station Model
Dew Point – measure of the moisture in the air; it is the temp the air must cool to in order to reach saturation

18. Weather Station Model
Wind Direction & Speed – the direction FROM which the wind blows and its speed (in knots)

19. Weather Station Model Observed Weather – describes precipitation
Cloud cover – percentage of the sky covered with clouds