1. Weather and Climate Air Masses and Fronts Day 7 12/7/10

2. Weather Fronts Objectives Today I will be able to: – _________________ the factors that characterize ______________ – Analyze the development of _________________when air masses meet

3. Weather Fronts Key Points Air masses are characterized based on their __________________ and __________________ Air masses pick up the characteristics of the land they go over – Ex: a cold, dry air mass that moves over warm, tropical waters will become _______________________________ ______________ are boundaries that separate air masses – ___________fronts are shown by a line with semicircles – Cold fronts are shown by a line with triangular points – Along a front, _______________is always forced upward – Along cold fronts, precipitation is generally heavy, but short-lived

4. Air Masses and Weather Weather patterns result from the movement of large bodies of air called ___________________ Air masses are characterized by similar ________________ and amounts of __________________at certain altitudes. When air masses move, the ___________________ of the air mass change and the ___________________ in the areas over which they move changes

5. Starts off at - 46 0 C Ends up at 70 0 C

6. Air Masses and Weather – Example of air mass/weather interaction: – A cold, dry air mass moves over warm, tropical waters  The air mass becomes ________________and ____________  The weather over those waters becomes ___________ and ______________ You try… – A warm, dry air mass moves over a cold, wet area  The air mass becomes ______________ and _______  The weather over that area becomes ____________ and ____________

7. When air masses meet… Fronts When two air masses ____________, they form a _______- the ____________________ that separates the two There are 4 types of fronts – ________________ fronts

8. Fronts Warm fronts – Form when _____________ air moves into an area ________________ covered by ________________ – Shown on a weather map by a ______ line with ________________ pointing toward the ________________ air Warmer air Colder air

9. Fronts Warm front

10. Fronts Warm fronts – As the _______________________________ air rises, it cools  This produces clouds and frequent precipitation – Warm fronts move __________, so the precipitation is ________________ over a ________________ area for a _________ period of time

11. Fronts Cold fronts – Form when _________, dense air moves into an area _______________ occupied by ____________air – Shown on a weather map by a _______ line with ________________ pointing toward the _____________air Colder air Warmer air

12. Fronts Cold Front

13. Fronts Cold Fronts – Move much __________________ than warm fronts – Associated with ___________________ that is _______________

14. Fronts Stationary Fronts – Form when the flow of air is neither toward the cold air mass, nor toward the warm air mass – The front ______________________ – Shown by __________________on one side and _________________on the other – Gentle to moderate precipitation

15. Fronts Occluded Front – Forms when a cold front ______________ a warm front – ____________ weather patterns

16. Check Ins 1.Air masses are characterized by what properties? 2.How do the properties of the land air masses travel over change the air mass? Give an example of this situation. 3.What are the boundaries between air masses called? What are the four types? What type of air is always forced up? 4.Which (from #3) is associated with short-lived, heavy precipitation? 5.Draw the symbols for each type of front.