Activities

1. What is the jet stream? How does it affect the North America?
   
   
2. What are trade winds?

3. How does barometric pressure help forecast weather?
   
   
4. How do global wind patterns relate to the climates of the rainforests and deserts?

5. How do ocean currents affect temperature? Give an example.
   
   
6. How does moisture and temperature affect the onset of lake effect snow? Give an example of a region affected by lake effect storms.

Answer Key/Rubric

1. A jet stream is a narrow belt of high speed winds that moves from west to east in the upper troposphere/lower stratosphere.  The jet stream can move cold, artic air more southward that it typically does, as far down as Kentucky. In the summer can pull warm, tropical air more northward, up into Canada
   
   
2. Trade winds blow from east to west.  As warm air rises around the equator, it begins to cool and sink. The sinking air causes winds to produce at the Earth’s surface, blowing back towards the equator. 

3. Sample response: If barometric pressure is low, clouds, precipitation or other stormy weather is likely.  If barometric pressure is high, clear and calm conditions can be expected.
   
   
4. Sample response: Due to the trade winds and the humidity by the equator, water vapor in the air at this location where most rain forests are located condense and form precipitation just about daily.  Most of the deserts are located approximately 30° from the equator.  The winds at this region cause the air being pulled back to the surface to be dry, therefore the desert receive very little precipitation.

5. Sample response: Ocean currents affect temperature because they move hot or cold water from one place to another.  As warm water travels north, it warms the water and air that it interacts with.  Convection currents are responsible for this movement. As warm air rises and cools, it eventually sinks as it cools again.  This continuous pattern forms a circular motion which allows for the transfer of the heat, producing warmer or cooler temperatures.
   Examples include, but are not limited to:

• The Gulf Stream originates in the Gulf of Mexico, and transfers the warm air and water along the eastern coast of the United States, then across the Atlantic to Europe.
• The Humboldt Current is a cold ocean current that flows northward along the western coast of South America. These currents transfer cooler air, therefore are responsible for the cooling climates of western South American countries including Peru, Ecuador, and Chile.

6. Sample response: Lake effect snow occurs when a cold air mass moves over warmer lake water.  The extreme temperature difference causes the air closest to the water to warm up. This warmer air mass picks up moisture in the form of water vapor. This water vapor rises into the cooler air above, causing precipitation in the form of snow to be deposited.
   Examples include, but are not limited to:

• The Great Lakes region of the United States. As cold air masses move across the warmer lakes, areas to the east generally are affected by lake effect snow, such as Buffalo, NY.