1. Weather
vs.
Climate

2. Weather is....
Weather is the day-to-day state of the atmosphere, and its short-term (minutes to weeks) variation
Weather includes sunshine, rain, cloud cover, winds, hail, snow, sleet, freezing rain, flooding, blizzards, ice storms, thunderstorms, steady rains from a cold front or warm front, excessive heat, heat waves and more

3. Climate is....
statistical weather information that describes the variation of weather at a given place for a specified interval
Climate may include precipitation, temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and hail storms over a long period of time.

4. Weather vs. Climate in NC
Monday morning:
Sunny in the morning...Then becoming partly sunny. Highs in the lower 70s. East winds around 5 mph
Monday evening:
Partly cloudy. Lows in the upper 40s. Light and variable winds...Becoming east around 5 mph after midnight.
Climate
North Carolina has a humid, subtropical climate. Winters are short and mild, while summers are usually very sultry; spring and fall are distinct and refreshing periods of transition. In most of North Carolina, temperatures rarely go above 100°F (38°C) or fall below 10°F (–12°C)

5. Main points to remember as we learn about weather:
The sun warms the earth’s surface and therefore all the air above the surface
The earth is warmed most at the equator and least at the poles---why?
The air above land is warmed more quickly than air above water.
Warm air expands and rises, creating an area of low pressure; cold air is dense and sinks, creating an area of high pressure

6. Air Mass
large body of air that has similar temperature and humidity properties throughout
Properties of air masses, however are modified as they move over areas outside where they originate
Source regions = regions where air masses develop their characteristics
– need large areas with similar characteristic

7. Air Mass Classification
Air masses have 4 major classifications
Polar (P)
Tropical (T)
continental (c) or maritime (m)
Arctic (A) - extremely cold air masses

8. Air Mass Classification
Air masses are classified according to their source regions:
Warm and dry continental tropical
Warm and humid maritime tropical
Cold and dry continental polar
Cold and humid maritime polar
Arctic
All five of these can be found in North America

9. Air Masses
Air masses are masses of air that have the same characteristics of the surface over which it develops

10. Wind Systems
Air flows from areas of HIGH pressure to areas of LOW pressure; this creates wind
Winds are named for the direction from which they flow.
Easterlies flow from the East to the West

11. Jet Stream
A high altitude, narrow, westerly wind band that occurs above large temperature contrasts and can flow as fast as 185 km/h.

12. Coriolis Effect Caused by the Earth’s rotation
Pulls the wind to the right in the northern hemisphere
Pulls the wind to the left in the southern hemisphere
Strongest at the Poles
None at the Equator

13. Example of Coriolis Effect

14. Air Pressure
Warm air= expanding or rising air= leaves behind L pressure
Cold Air=sinking air= leaves an area of H pressure
Air Pressure/Atmospheric Pressure is measured with a barometer

15. Wind Movement
Uneven heating of the earth’s surface causes some areas to be warmer than others.
As we know, warm always follows cold to share it’s warmth- when this happens in the atmosphere, wind happens!

16. What causes winds?
A wind is a horizontal movement of air from a area of high pressure to an area of low pressure
It is this difference in pressure that makes the air move=wind
Winds are measured by direction and speed
The anemometer is the tool we use to measure this
Wind chill=↑ cooling the wind causes

17. Local Winds
The land cools and heats faster than the ocean. Water holds heat longer than land, and takes longer to heat or cool.
SEA BREEZE
During the day, the land gets hotter faster than the water. The heated air rises, leaving behind an area of low pressure. Wind from the cooler sea blows in to take the place of that warmer air. These happen during the day!

18. Land Breezes
At night the lands cools off faster than the sea. Cool air sinks creating an area of high pressure. Wind blows from the land to the sea.

19. STOP

20. Global Circulation and Wind Systems
Solar energy is at its greatest around the equator---Why?

22. Global Winds: Wind belts: Horse Latitudes= 30°N and S of
equator =calm winds= worlds
desert areas
Jet Streams= 10km above the
surface blow from the west to the east

23. Some of the air moves back towards the equator as it sinks...
Tradewinds:
Where do you think
they got their name?
Who were these winds
particularly important to?

24. There was an area that sailors avoided with their lives...
THE DOLDRUMS... is the area around the equator where the wind completely dies out... which meant death as soon as the fresh water ran out.

25. Weather Foldable
Warm front
Cold front
Occluded front
Stationary Front

26. Fronts: the boundary between 2 air masses
This is the symbol on a map for a warm front
Warm Front: warm air slides over departing cold air- large bands of precipitation form

27. This is the symbol for a cold front
Cold Fronts
Cold air pushes under a warm air mass. Warm air rises quickly=narrow bands of violent storms form

28. This is the weather map symbol for an occluded front
2 air masses merge and force warm air between them to rise quickly. Strong winds and heavy precipitation will occur

29. This is the weather map symbol for a stationary front
Warm or cold front stops moving. Light wind and precipitation may occur across the front boundary

30. Reading a weather map
ISOBAR= connects areas of equal pressure BAR comes from BARometric pressure

31. Reading a weather map...
Isotherm: Connects areas of equal temperature; therm means temperature