Name ________________________________
Ms. De Pinto
Period ______
Date ____________________
Air Masses & Severe Weather Webquest
Part 1: Air Masses
Site 1: Air Masses - The Basics
1. What is an air mass?
*Note: If any of the
below links do not
work, please Google
the question to find
its answer.
2. Where do polar and tropical air masses develop? (Give the approximate latitudes.)
3. For each of the four air masses, what is the description this website gives? Indicate where these
would be found in the US.
Name/Abbreviation
cP =
cT =
mP =
mT =
Description
Location in US
Site 2: Air Masses - More Information
5. This site describes five basic types of air masses. You have already described 4 of these earlier.
Describe the 5th type.
Name/Abbreviation
Description
Location in US
6. Label the air masses on the map with the appropriate abbreviation.
1.
2.
3.
4.
5.
6.
7. What do the letters “K” or “W” mean when attached to an air mass?
8. When does America typically have its most violent weather? Why?
Site 3: Air Mass Visualizations
9. In the first illustration, what kind of air mass is passing over the region? What type of weather will it
bring?
10. In the second illustration, what kind of air mass is passing over southern California? What type of
weather will it bring?
11. Go to the website: http://www.weatherquestions.com/What_causes_high_pressure.htm to find
out what causes a high pressure air mass.
a. What causes an air mass to have a high pressure?
12. The website http://www.weatherquestions.com/What_causes_low_pressure.htm will help you
answer the following question:
a. What causes an air mass to have a low pressure?
13. Look at the pictures on this site:
https://www.lordgrey.org.uk/~f014/usefulresources/aric/Resources/Teaching_Packs/Key_Stage_4/We
ather_Climate/03.html#:~:targetText=that%20air%20moves%20from%20high,see%20also%20lesson%20
2)%3B.
Does air move from high pressure to low, or low to high?
Part 2. Global Winds
14. a. http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/global_winds.rxml
What are the Global Winds? ______________________________________________________________
b. Label B – L in the diagram below.
c. Jet Stream
i. Go to the following website http://www.intellicast.com/National/Wind/JetStream.aspx
What is the jet stream?
What does the jet stream map show us?
About how fast is the jet stream moving today and in what direction?
Part 3. Coriolis Effect
15. The Coriolis Effect affects Earth’s winds. Read the information at this website to find out about the
Coriolis Effect: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/crls.rxml . The video at the bottom
will give you a visual of the Coriolis Effect.
a. Click on the “Pressure Gradient” link. What is the direction of the net force between two
pressure systems?
From
pressure to __________ pressure.
b. Click on the blue highlighted “High” link. What is a High Pressure Center & what does it mean?
c. In the video, why does the ball not roll straight across the merry-go-round?
d. How is the Earth similar to the merry-go-round? (look at the figure)
e. Wind is an object that is affected by the Coriolis Effect. What happens to winds in the
Northern Hemisphere as a results of the Coriolis Effect? (HINT: Which way do they bend?)
16. Use the animation at the following website to help you find out how the Coriolis Effect affects
wind: http://www.classzone.com/books/earth_science/terc/content/visualizations/es1905/es1905page01.cfm
(Enable Adobe Flash Player)
a. Which way does the Coriolis Effect deflect wind in the Northern Hemisphere?
Part 4. Pressure Centers and Weather
17. Go to the website listed here:
http://ww2010.atmos.uiuc.edu/(Gh)/wx/surface.rxml . Then, find the
picture that says “Sea Level Pressure with IR satellite”. Click on this
figure to bring up a new window. Click on the button that says
“Animate”. Choose “96 frames”. Answer the following questions:
a. (Do not play the animation yet.) This map shows you isobars and cloud cover. Click on the
? help to explain what an isobar is.
b. Look at the map and find Chicago. Between which two isobars is Chicago?
c. Press “Play” on the window, and watch where the clouds travel. Do the clouds tend to be
near High pressure centers (H) or Low pressure centers?
18. This website will help explain why High pressure centers usually mean good weather, and Low
pressure centers usually mean bad weather: http://www.usatoday.com/weather/tg/whighlow/whighlow.htm .
Go here and read to discover why this is true, and then answer the following questions:
a. Air descends (comes down) at High pressure areas. Why does descending air not allow for
clouds to form?
b. Air ascends (goes up) at Low pressure areas. Why does ascending air allow for clouds to
form?
c. Use diagram to determine the direction of wind motion.
What is the direction around a High pressure system?
d. What is the direction around a Low pressure system?
Site 4: Front Illustrations
19. Click on the “Cold Front.” What happens in the illustration? (Enable Adobe Flash Player)
20. Click on the “Warm Front.” What happens in the illustration? (Enable Adobe Flash Player)
21. In both the cold front and the warm front, warm air rises and cold air stays near Earth’s surface.
How are they different?
Site 5: Cold Fronts
22. What is a cold front and in what direction does one typically move?
23. How are cold fronts represented on a weather map?
24. From the chart at the bottom of the page, what happens to the wind as a cold front passes
through? What about the precipitation?
Site 6: Warm Fronts
25. What is a warm front and in what direction does one typically move?
26. How are warm fronts represented on a weather map?
27. Using the chart at the bottom of the page, when a warm front passes through an area, what
happens to the temperature and precipitation levels in that area?
Site 7: Stationary Fronts
28. What is a stationary front and what type of weather does one typically bring?
29. What is the weather map symbol for a stationary front?
Site 8: Occluded Fronts
30. How does an occluded front form?
31. What is the weather map symbol for an occluded front?
Site 9: Fujita Scale
14. What kind of storms are classified on the Fujita Scale?
15. Describe the damage done at each scale rating:
F0:
F1:
F2:
F3:
F4:
F5:
Site 10: Tornado Alley On the top right, click on the link for tornado alley (in green)
17. Look at the map. What 19 states make up tornado alley? (abbreviations are fine)
18. a. Which state gets the most tornadoes per square mile? ________________________________
b. Which state has the highest frequency of F3 & F4 tornadoes? ________________________________
Site 12: US Tornado Climatology
19. Where in the world can tornadoes happen?
20. Where in the world are tornadoes most likely to happen?
Site 13: Hurricane Watches and Warnings
21. What is the difference between a hurricane watch and a hurricane warning?
Site 14: What Can't We Stop Hurricanes?
22. Why can't we stop hurricanes?
Site 15: Intensity Scales
23. Which intensity scale is used for hurricanes?
24. If a hurricane has wind speeds of 103 mph, what category is the storm? ____________
Site 16: Review Quiz
33. Go to the above website and answer all 15 questions. When you finish, write down your score as
the number you got right (out of 15) and the percent (out of 100) it equals.
# Correct: _______________
Percent Score out of 100: _____________