Download Air Masses and Fronts

Air Masses and Fronts
CHAPTER 17-1
FRONTS
A FRONT is the boundary between two
different air masses
• Storms and changeable weather are
common
• Differences in air pressure, temperature
and humidity are common with fronts
• Four types of fronts are:
•Cold
•Warm
•Stationary
•Occluded
COLD FRONT

A cold air mass replaces a warm air
mass
• Showers and Thunderstorms are
common
• Cooler and drier air follows the front
WARM FRONT

A warm air mass replaces a cold air
mass
• Steady precipitation for several hours or
days
• Weather tends to be warm and humid
STATIONARY FRONT

A front that does not move or barely
moves
• Two air masses in a “standoff” with neither one
moving
• Periods of rain, drizzle and fog are common
• Several days of clouds and precipitation are
likely
• Temperatures remain constant and winds are
gentle
OCCLUDED FRONT

Occurs when a warm air mass is
caught between two cooler air
masses
• Warm air is “cut off” from the ground
• Periods of rain or snow are common
warm
warm
FRONT SYMBOLS
WEATHER MAP SYMBOLS
ANTICYCLONES
High pressure centers of dry air
• Usually called “HIGHS”
• Appears as an “H” on a weather map
• Winds spin clockwise in N. Hemisphere
• Areas of sinking air in the center
• Dry, clear weather is likely
ANTICYCLONES
HIGH PRESSURE AREAS
CYCLONES
Low pressure areas
• Usually called “LOWS”
• Appears as an “L” on a weather map
• Winds spin counterclockwise in N.
Hemisphere
• Areas of warm, rising air in the center
• Clouds and precipitation are likely
CYCLONES
LOW PRESSURE AREAS
REVIEW # 1
1) The air mass that forms over central Canada
is called_________
2) The front that brings rising temperatures and
steady rain is the ______front
3) The air mass that is warm and humid is
called__________
4) The front that brings showers and cooler
temperatures is called a ______front
5) The front that doesn’t move is called_______
6) An air mass that is warm and dry is called ?
7) Clear and dry weather is common to a _____
REVIEW # 2
1)
2)
3)
4)
5)
6)
What are the symbols used on a weather
map for the four types of fronts?
In what direction do LOWS spin?
How many air masses are found in an
OCCLUDED FRONT?
What are the weather conditions does a
CYCLONE bring?
Air masses move across the U. S. from
________ to __________.
What kind of air mass is outside today?
REVIEW # 3







1) Maritime means ________________.
2) Tropical means________________.
3) Continental means_______________.
4) Polar means________________.
5) Several days of clouds and precipitation
would be likely with a _________ front.
6) Which air mass forms over the Gulf of
Mexico? ______
7) An “L” on a weather map is called ___.
REVIEW
ANTICYCLONE
1) What direction does it spin in the northern
hemisphere? ______________
2) What kind of weather does it have? ________
___________.
3) What is another name for this feature?_______
_____________.
REVIEW
CYCLONE
1) What direction does it spin in the northern
hemisphere? ___________________.
2) What kind of weather does it have?_________
______________.
3) What is another name for this feature?_______
__________________.