1. Where are they?
Why is there no weather?

2. Meteorology The study of weather
Good sites for weather info:
weather.com
nws

3. Describe the weather outside right now
The variables measured are:
Temperature
Humidity (Dew point and RH)
Pressure (High /Low)
Wind (speed and direction)
Precipitation (rain, sleet, snow, etc)
Cloud (percentage and type)
Will these variable change over the next minute? Hour?day?week?

4. Air Temp Instrument: Thermometer
Temp decreases as you increase in altitude

5. What affects our temperature?
Latitude (East Rockaway vs Miami)
Altitude (ER vs Mt Marcy)
Closeness to Ocean (ER vs Elmira)
Cloud cover (Clear vs cloudy)
Land use

6. Humidity Absolute Humidity – amount of water vapor in the air
Relative Humidity (RH) – amount of water vapor in the air vs the amount it can hold at a specific temp.
Dew Point (DP) – the temp to which air has to cool for dew to form
What is the relationship between DP and RH?
Instrument: Sling psychrometer

7. DP and RH Dew Point Relative Humidity
The closer the DP temp is the air temp more likely clouds/dew/precip will form.
How does this relate to RH?
Relative Humidity
Written as a percent.
The closer to 100%, the more likely clouds and precip.

8. Sling Psychrometer
Dry Bulb – AirTemp
Wet Bulb - fabric

12. Dry Bulb
Wet Bulb
Wet Bulb Depress.
Relative Humidity
Dew Point Temp 1
12C
7°C 2
22°C
20°C 3
18°C
12°C 4
6°C
5°C 5
21°C 6
16°C
66% 7
19°C 8
17°C
13°C
63%
10°C 9
86 F
77 F 10
64 F
54 F

13. 11
26°C
24°C 12
16°C
12°C 13
30°C
21°C 14
0°C
-2°C 15
25°C 16
11°C
6°C 17
15°C 18
8°C
4°C 19
1°C
14°C 20
-1°C

16. Barometric Pressure
Force or weight of air pushing on the surface of earth
Pressure decreases as altitude increases (why)
Moist air light (Low)
Dry air heavy (High)
Instrument: barometer

17. Barometric Pressure

18. Pressure Air flows from High to Low causing wind! H L High (H)
Dry conditions
Air circulates clockwise and outward
Air is sink from above
Low (L)
Wet Condition (Precipitation)
Air circulates counterclockwise and inward
nws-goes sat
Air flows from High to Low causing wind!
H L

19. http://www. newmediastudio

21. Wind Horizontal movement of air.
Caused by difference in heating of Earth (difference in air pressure [H to L])
Sun heats Earth, Earth heats atmosphere
(conduction, convection, radiation)
Instrument: Anemometer,
Wind vane

22. Insolation and re-radiation

23. Local vs Planetary Winds
examples
Land and Sea Breezes
Mountain Ranges
Planetary
Move weather systems
P.14 esrt

26.
Land and Sea Breeze

27. Mountain Ranges

28. Precipitation and Clouds
Clouds form when rising air reaches the dew point temperature and there are condensation nuclei (particles of dust, pollen, ash, etc) present.
Precipitation occurs when the air is saturated and water vapor becomes either a solid or a liquid.
What is condensation? What are other phase changes? When is energy released? Absorbed?

33. This method of cloud classification was proposed by Luke Howard (1803) who named the clouds based on their form:
Cirrus - curl
Stratus - layer
Cumulus - heap
Nimbus - rain
and on their height:
High
Middle
Low
Contrails fall into the category of cirrus as they are high level clouds that consist entirely of ice crystals

35. Units millibars, inches, atmospheres