ANSWER KEY
Study Guide – Air Masses, Fronts & Station Models
1. What is an air mass? An air mass is a large body of air with uniform temperature and uniform moisture.
2. If a continental polar air mass moved over the Ashburn area, what would change? Temperatures and humidity
would decrease. (It would become colder and drier)
3. How are Air Masses classified? Air masses are classified by temperature and humidity.
4. Which air mass causes most of the precipitation in the eastern United States? Maritime Tropical over the
Caribbean Sea.
5. Which two air masses mainly influence much of the east coast? Maritime Tropical and Continental Polar.
6. Why does the Continental Tropical air mass centered over Mexico have little influence on weather in the east?
Air Masses don’t travel far from their source regions.
7. Air masses that form over land are called Continental; Air masses that form over water are called Maritime
8. What is a warm front? The boundary between advancing warm air mass & a colder air mass it is displacing.
9. What kind of front forms when a cold front overtakes a warm front? An occluded front
10. What happens along stationary fronts? The front stops moving forward, producing clouds & precipitation.
11. What kind of weather is associated with cold fronts? Wind, heavy rain, Thunderstorms, Lightning, clearing and
colder air after front passes.
12. What forms at the boundary between two different air masses? A front
13. Which types of fronts are most likely to produce thunderstorms? Cold and Occluded fronts
14. Which type of front is the most complex because it involves 3 different air masses? Occluded fronts
15. Which type of front would you see cirrus clouds a day before rain showers? Warm fronts
Fill in the blank:
16. The Continental tropical air mass can cause very hot, drought-like conditions during summer on the Great Plains.
17. Heavy rain, on the windward slopes of mountains near the Pacific NW is caused by the uplift of air in Maritime polar
air masses.
18. A Cold or Occluded front can bring heavy rain and thunderstorms.
19. At a(n) Stationary front, the flow of air stops moving forward.
Please answer the following in complete sentences:
20. a) A warm, moist air mass moves northwest over a cool, dry area. How will the air mass affect the temperature and
humidity of the area it moves over?
It will bring warmer temperatures and higher humidity (and possibly rain)
20. b) How will this affect the temperature and humidity of the air mass itself?
The air mass will eventually cool down and become drier.
Use the figure below to answer the following questions:
C
A
G
E
21. Which air masses bring cool, dry air to large
regions of eastern North America?
Continetal Polar and Continental Arctic (air
masses labeled C & E)
22. The air masses labeled A & G are classified as
Maritime Polar
23. The air masses labeled B and F bring warm, moist
air to the United States.
D
F
B
24. The air mass labeled D would be represented by
the symbol cT.
25. The air mass labeled E would be represented by
the symbol cP.
Below is a diagram showing a cross section of two fronts commonly found along a low pressure weather system
in the United States. Complete the diagram by labeling and drawing the information requested and them answer
questions 26-30.
*Draw and label the following on the diagram:
Cumulonimbus Clouds, Nimbostratus Clouds, Cirrus Clouds, Cold Front, Warm Front, Clear Skies
26. Along which front would thunderstorms and possible tornadoes be found? Cold Front
27. Which city is having gentle rains? City C
28. Which city is having heavy rainfall? City A
29. Which city will experience the weather along the cold front next? City B
30. Draw the symbol meteorologists use to indicate each of the following fronts on a weather map.
Stationary Front
Warm Front
Cold Front
Occluded Front
Record the following weather conditions from the station model provided:
SE - Wind Direction
75oF - Temperature in (Fo)
50% - Cloud Coverage (%)
66oF - Dew point (Fo)
1002.5 mb - Pressure (mb)
-1.3 mb - Pressure Trend (mb)
25 knots - Wind Speed (knots)
Thunderstorms - Current Weather