Weather and ClimateAir Masses and Fronts

Day 712/7/10

Weather FrontsObjectives

• Today I will be able to:–_________________ the factors

that characterize ______________–Analyze the development of

_________________when air masses meet

Weather FrontsKey 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

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

Starts off at -460C

Ends up at 700C

Air Masses and Weather– Example of air mass/weather interaction:– A cold, dry air mass moves over warm, tropical watersThe air mass becomes ________________and ____________The weather over those waters becomes ___________ and

______________

You try…– A warm, dry air mass moves over a cold, wet areaThe air mass becomes ______________ and _______The weather over that area becomes ____________ and

____________

When air masses meet… Fronts

• When two air masses ____________, they form a _______- the ____________________ that separates the two

• There are 4 types of fronts– ________________ fronts– ________________ fronts– ________________ fronts– ________________ fronts

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

Fronts

• Warm front

Fronts

• Warm fronts– As the

_______________________________air rises, it coolsThis produces clouds and frequent

precipitation–Warm fronts move __________, so the

precipitation is ________________ over a ________________ area for a _________ period of time

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

Fronts

• Cold Front

Fronts

• Cold Fronts–Move much __________________ than

warm fronts–Associated with ___________________

that is _______________

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

Fronts

• Occluded Front–Forms when a cold front ______________

a warm front–____________ weather patterns

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.