1. *Refer to Chapters 10 & 11 in your Textbook

2. Learning Goals: 1. I can analyze how wind circulation and coriolis develop air masses. 2. I can differentiate between the 4 types of weather fronts. 3. I can use weather fronts and pressure systems to make weather predictions.

3. Wind Circulation: Warm, moist air rises Cold, dry air sinks This creates a circulation of air called an air cell: 1. Hadley Cell: equator 2. Ferrel Cell: mid-latitude 3. Polar Cell: poles

4. Wind Circulation: *Label Map!* Coriolis and the air cells heating and cooling allow the winds to travel in specific directions Tradewinds: occurs along the equator, carries cool air from the northeast to the southwest Westerlies: occurs at the mid-latitudes (above the Tropic of Cancer in the North), carries warm air from the southwest to the northeast Polar Easterlies: occurs at the north and south poles, carries extremely cold air from the northeast to the

5. Wind Circulation:

6. Air Masses: An air mass is a volume of air defined by its temperature, location, and water vapor content m (maritime): moist, over the ocean c (continental): dry, over the land T (Tropical): warm air P (Polar): cold air A (Arctic): coldest air

7. Weather Fronts: Weather fronts are boundaries between two air masses of different temperature 4 Types: 1. Warm Front 2. Cold Front 3. Occluded Front 4. Stationary Front

8. Weather Fronts: Warm fronts occur when warm air replaces cold air The warmer air rises creating small clouds and light rain that can last a long time, and an increase in humidity Warm fronts move much slower than cold fronts

9. Weather Fronts: Cold fronts occur when cold air replaces warm air Cold fronts move much faster than warm, which causes the warm air to rise vertically quickly This creates heavy clouds and thunderstorms that are quick, before the air cools down and humidity decreases

10. Weather Fronts: Occluded fronts occurs when a cold front over takes a warm front This happens when very cold, cool, and warm air collide with each other Acts like a cold front creating heavy clouds and rain or snow

11. Weather Fronts: Stationary fronts occurs when a cold front meets a warm front, but there is not forward movement (“standing still”) Acts like a warm front creating clouds and light rain or snow that can last a long time

12. Pressure Systems: What else can we use to predict weather patterns besides weather fronts? = Air Pressure Average Air Pressure = 980 – 1050 mb (millibars) High Pressure System: good weather, low humidity, low clouds, no precipitation Low Pressure System: bad weather, high humidity, many clouds, rain, snow, or cyclones

13. Pressure Systems: