Meteorology - Chapter 8 - Air Masses
49) What is an atmospheric river?
A) An atmospheric flow that transports vast amounts of moisture to regions outside of the tropics.
23) Where do North American cA air-masses originate?
A) Arctic basin and green land ice cap
38) A nor'easter typically occurs when:
A) NE winds associated with a low-pressure system draw mP air into the northeastern United States.
56) If an air mass passes over a surface that is warmer than it is, what can be said about the changes likely to happen within that air mass?
A) The air mass is likely to become more unstable.
58) If the lowercase letter k appears at the end of an air mass identification code, what can be said about the changes likely to happen within that air mass?
A) The air mass is likely to become more unstable.
64) Lake-effect snowfall is caused by:
A) air mass modification related to the differential heating of land and water.
31) Siberian Express is the term used when:
A) an outbreak of bitterly cold air from Canada intrudes over a large part of the United States.
30) Which air mass does not usually influence weather in the United States during the summer?
A) cA
24) Which two air masses are bitterly cold and very dry during winter?
A) cA and cP
57) Which of these is NOT a process by which air masses are modified?
A) calm winds
18) An mP air mass is:
A) humid and cold.
6) An air-mass source region:
A) is characterized by a general stagnation of atmospheric circulation.
26) Which of the following is not an air mass that influences North America?
A) mA
36) The ________ air mass often originates as a different air mass in Siberia and is subsequently altered.
A) mP
45) What air-mass contributes to the formation of thunderstorms in the central U.S.?
A) mT
41) Which region of origin for mT air masses has the most impact on North American weather?
A) mT air masses from the Gulf of Mexico
59) A warm, moist air mass from the Gulf of Mexico that moves over the land in the southeastern U.S. during the summer is likely to be classified as:
A) mTk.
54) Topography and the upward and downward movements of cyclones and anticylones create ________ modifications of air masses.
A) mechanical (dynamic)
53) Air mass modifications produced by cyclones or topography rather than surface temperatures are called:
A) mechanical modifications.
65) Where would you expect to find the greatest amount of lake-effect snowfall?
A) on the leeward shores of the Great Lakes
10) The area where an air mass originates is called a:
A) source region.
28) Air masses with cA and cP designations are typically:
A) stable
12) Characteristics of an air mass source region include:
A) uniformity of surface.
68) To qualify as an air mass, a large body of air must have the identically same temperature at the same altitude throughout the air mass, even if the body of air is 1,000 kilometers wide.
Answer: FALSE
72) The physical properties of an air mass are independent of its place of origin.
Answer: FALSE
73) A region dominated by cyclones is more likely to produce an air mass than a region dominated by anticyclones.
Answer: FALSE
76) Maritime air masses form over landmasses.
Answer: FALSE
78) The symbol used when classifying Maritime Polar air masses is MP.
Answer: FALSE
80) As wintertime cP or cA air moves outward from its source region, it carries its warm wet weather to the United States.
Answer: FALSE
81) cP and cA air masses are never experienced in the southern U.S.
Answer: FALSE
82) Continental polar air masses do not form in the summer in North America.
Answer: FALSE
83) Siberian Express weather events are generally confined to Alaska and western Canada.
Answer: FALSE
84) Maritime polar (mP) air masses have their greatest influence in the eastern United States.
Answer: FALSE
89) Maritime tropical (mT) air masses are the most important source of moisture along the Pacific Coast.
Answer: FALSE
90) The Pineapple Express is responsible for supplying most of the moisture on the east side of the Rocky Mountains.
Answer: FALSE
91) cT air masses are stable.
Answer: FALSE
94) An air mass can not be modified when moving across country.
Answer: FALSE
96) The properties of air masses change little, even if they travel thousands of kilometers.
Answer: FALSE
99) Lake-effect snow occurs only during the early spring.
Answer: FALSE
100) Lake-effect snowfall is created as a direct result of air mass modification.
Answer: TRUE
67) An air mass is an immense body of air characterized by relatively homogeneous temperature and moisture content.
Answer: TRUE
69) The boundary of an air mass is a region of especially active weather.
Answer: TRUE
70) In the middle latitudes, atmospheric disturbances occur at the boundary zones separating air masses.
Answer: TRUE
71) The majority of the continental U.S. is not an air mass source region.
Answer: TRUE
74) Air masses are identified by two-letter codes.
Answer: TRUE
75) Maritime Arctic air masses do not form very often.
Answer: TRUE
77) Maritime air masses have a higher water vapor content than continental air masses.
Answer: TRUE
79) The lower-case letter m or c is used to designate the nature of the surface in the source region and hence the humidity characteristics of the air mass.
Answer: TRUE
85) Orographic precipitation in the western U.S. is often associated with the Pacific mP air mass.
Answer: TRUE
86) The stormy winter weather associated with an invasion of mP air from the Atlantic into an area east of the Appalachians and north of Cape Hatteras is known as a nor'easter.
Answer: TRUE
87) mP air masses over the northeastern United States produce stable, clear skies in the summer and heavy snowstorms in the winter.
Answer: TRUE
88) The mT air masses from the Gulf-Caribbean-Atlantic source region greatly affect the weather of the United States east of the Rocky Mountains.
Answer: TRUE
92) cT air masses are hot and dry.
Answer: TRUE
93) Continental tropical (cT) air masses are associated with very dry summertime conditions in the southern Great Plains.
Answer: TRUE
95) When an air mass is warmer than the surface over which it is moving, its lower layers are chilled.
Answer: TRUE
97) When an air mass is warmer than the surface over which it moves, an inversion is likely.
Answer: TRUE
98) An air mass with the designation k is likely to become more unstable.
Answer: TRUE
63) Which of the following statements is TRUE of lake-effect snowfall?
B) Along the Great Lakes, lake-effect snowfall usually only occurs within 80 km of the leeward lake shores.
48) The ________ is characterized by a strong jet stream pulling mT air from Hawaii towards California.
B) Pineapple Express
19) Why is Maritime Arctic left out of the air-mass classifications?
B) They only rarely occur.
39) All of the following accompany a classic New England nor'easter EXCEPT:
B) a strong storm forming in Canada and moving into New England from the North
1) When an area is experiencing several consecutive days of rather constant weather, it is experiencing:
B) air-mass weather.
61) "Lake-effect" snow is associated with the ________ air mass.
B) cP
50) In North America the ________ air mass typically forms only in the summer.
B) cT
29) What weather is associated with cA air masses?
B) cold spells in winter
55) An air mass is often modified as it moves over the earth's surface. This modification is largely due to:
B) contact with the new surface below.
44) Lines connecting places having equal rainfall on a map are called:
B) isohyets.
37) The ________ air mass may produce an occasional "nor'easter" in the winter.
B) mP
33) Consider the map above. What air mass is the most likely to be found in Florida, just ahead of the cold front?
B) mT
9) Air-mass source regions are least likely to exist in:
B) middle-latitude regions.
14) Which air mass code letter is paired with the wrong word?
B) t = temperate
15) Air masses are identified by a pair of letters, one lowercase and one uppercase. The
B) the approximate latitude/temperature of the air mass source region.
42) While on vacation in Florida, you experience several days of weather with maximum temperatures of 90°F and dew points above 65°F. What educated guess could you make about the weather?
C) It is caused by an mT air mass.
35) Why are maritime air masses from the north Atlantic of only limited concern for weather in the U.S.?
C) Prevailing winds move them away from the U.S.
66) Which one of the following conditions would enhance the development of a lake effect storm?
C) a large temperature gradient between the lake surface temperature the lower atmosphere
51) Which air mass causes very dry conditions in the southern Great Plains of the United States?
C) cT
16) Compared to continental air masses with the same air temperature, maritime air masses:
C) have higher water vapor content.
40) Which air mass is unstable in the winter but stable in the summer?
C) mP
22) An air mass from the Gulf of Mexico is called:
C) mT.
3) The two most important properties that should be relatively homogeneous at the same altitude in an air mass are:
C) moisture content and temperature.
46) An mT air mass moving onto land in the Southeastern United States during the summer time typically becomes:
C) more unstable.
13) An ideal source region of air masses should be:
C) physically uniform.
4) An air mass is a body of air with:
C) similar values of temperature and moisture at any given altitude.
60) When an air mass is warmer than the surface over which it is moving:
C) the air becomes more stable.
62) In the United States, lake-effect snows occur over which area?
C) the leeward shores of the Great Lakes
34) Most mP air masses that influence the U.S. originate over:
C) the north Pacific.
17) A cT air mass is:
C) warm and dry.
32) What term would a meteorologist give to the weather event represented on the map above?
D) The Siberian Express
7) Which of the following criteria is NOT a characteristic of a good source region?
D) The area must frequently experience cyclones.
2) The usual size of an air mass is:
D) at least 1600 km across.
20) Which of the following air masses probably has the lowest water vapor content?
D) cA
27) The pronounced cooling that occurs on continents at high latitudes during winter leads to the formation of ________ air masses.
D) cP
21) The cP air-mass in North America originates in:
D) interior Alaska and Canada.
43) The ________ air mass provides much of the moisture for precipitation in the central and eastern United States.
D) mT
47) Most of the precipitation for the region east of the Rocky Mountains comes from:
D) mT air masses.
52) The stability of an air mass can be affected by:
D) mountain ranges, cyclones, and anticyclones.
8) Which of the following is not a good source region for air masses?
D) the central United States
25) The coldest and driest winter air-mass in North America is the:
E) cA.
5) The typical amount of time it takes for an air mass to pass over a given area is on the order of a few:
E) days.
11) Air mass source regions tend to be dominated by:
E) slow moving anticyclones.
