Deck 9: Air Masses and Fronts

Question 1

Because of differences in ________ some air masses are more likely than others to yield precipitation.

A)temperature
B)pressure
C)stability and moisture
D)temperature and pressure

Answer 1

C

Question 2

Large bodies of air that share similar moisture and temperature characteristics are known as ________.

Answer 2

air masses

Question 3

Air masses

A)all originate from the same place.
B)require one to three months to form.
C)vary substantially in important characteristics on the horizontal dimension.
D)often have large vertical temperature gradients.

Answer 3

D

Question 4

The sources of air masses occur only in low and high latitudes because

A)middle-latitude weather is too variable.
B)middle-latitude weather is not variable enough.
C)there are no oceans in the middle latitudes.
D)there is insufficient contrast in surface type (land vs. ocean)in the middle latitudes.

Question 5

The passage of a front often brings

A)strange odors.
B)clear skies.
C)abrupt changes in temperature, humidity and wind.
D)abrupt changes in atmospheric composition.

Question 6

Fronts usually provide a lifting mechanism that can lead to the formation of

A)a radiation inversion.
B)large hailstones.
C)a large-scale weather circulation.
D)clouds and precipitation.

Question 7

Air-mass source regions

A)are most common at mid-latitudes.
B)are typically on the order of a thousand square kilometers in size.
C)typically require many days to form an air mass.
D)exist in winter, but not in summer.

Question 8

Different air masses have different stability because

A)the horizontal temperature variation within an air mass is fairly uniform.
B)the horizontal temperature variation within an air mass is not uniform.
C)the vertical temperature variation within an air mass is fairly uniform.
D)the vertical temperature variation within an air mass is not uniform.

Question 9

An "air mass" is a large body of air that has similar horizontal characteristics of

A)moisture and temperature.
B)temperature and density.
C)density and pollen.
D)moisture and winds.

Question 10

Which of the following are often associated with the passage of a frontal system?

A)rapid change in temperature
B)shift in wind speed and direction
C)change in moisture content
D)all of these

Question 11

Air masses are

A)large bodies of air with fairly uniform temperature and moisture characteristics.
B)large bodies of air with the same mass.
C)large bodies of air with fairly uniform pressure characteristics.
D)large bodies of air with fairly uniform wind characteristics.

Question 12

Warming and cooling of the atmosphere varies across the globe due to

A)ocean currents.
B)the unequal distribution of land and water.
C)global warming.
D)wind shear.

Question 13

Air masses are classified according to the ________ and ________ characteristics of their source regions.

Question 14

This is a typical number of air masses to be over the United States at one time.

A)one
B)five
C)12
D)22

Question 15

Heating or cooling of large bodies of air requires many days because

A)energy transfer is not an instantaneous process.
B)energy transfer is an instantaneous process.
C)the process takes place only during nighttime.
D)the process takes place only during daytime.

Question 16

The temperature,pressure and moisture characteristics of the atmosphere arise mostly from

A)the daytime exchange of energy and water vapor between the air and the surface.
B)the nighttime exchange of energy and water vapor between the air and the surface.
C)the continuous exchange of energy and water vapor between the air and the surface.

Question 17

Air-mass source regions are least likely to be found here.

A)high latitudes
B)middle latitudes
C)low latitudes
D)polar regions

Question 18

The boundary between two adjacent air masses is called

A)entrainment.
B)a front.
C)adiabatic.
D)an air strip.

Question 19

Why aren't air masses classified based on their pressure characteristics?

A)because sea-level pressure is fairly uniform across the globe
B)because temperature is fairly uniform across the globe
C)because moisture is fairly uniform across the globe
D)because both temperature and moisture are fairly uniform across the globe

Question 20

Air masses are generally named according to

A)the characteristics of their source regions.
B)the season of the year they form in.
C)the precipitation they produce.
D)all of these

Question 21

Meteorologists have grouped air masses into this number of major categories.

A)three
B)four
C)five
D)six

Question 22

Continental polar air-mass source regions are typically

A)warm.
B)free of snow in the winter.
C)cloudy.
D)dry.

Question 23

Continental polar air masses typically form in winter under all of the following conditions,except

A)over large, high-latitude land masses.
B)over snow-covered areas.
C)over areas that absorb large amounts of insolation.
D)over very cold areas.

Question 24

An air mass that formed over northern Canada would most likely be designated

A)cP.
B)mP.
C)cT.
D)mA.

Question 25

Which of the following air masses has short days and low sun angles during winter?

A)continental polar
B)maritime tropical
C)continental tropical
D)radiation inversion

Question 26

Which of the following air masses are dominant over the southeastern U.S.,especially in the summer season?

A)mP
B)cP
C)cA
D)mT

Question 27

List the sources of maritime air masses that affect North America.

Question 28

Why don't continental polar air masses form over Greenland?

A)Greenland isn't in the high latitudes.
B)Greenland isn't in the low latitudes.
C)Greenland is in the middle latitudes.
D)Greenland isn't large enough.

Question 29

________ air masses develop over warm ocean waters in tropical or subtropical regions.

Question 30

Why are all air masses labeled either "polar," "arctic" or "tropical"?

A)because heat exchanges occur only in the low and high latitudes
B)because energy exchanges occur only in the high latitudes
C)because heat and energy exchanges occur only in the low and high latitudes
D)because air masses don't form in the middle latitudes

Question 31

The arctic front

A)is relatively shallow.
B)produces substantial amounts of snowfall.
C)never penetrates further south than central Canada.
D)does not produce a temperature difference when it passes an area.

Question 32

The coldest air mass is

A)maritime polar.
B)continental tropical.
C)maritime tropical.
D)arctic.

Question 33

This figure illustrates the southward movement of a

A)continental tropical air mass.
B)continental polar air mass.
C)maritime tropical air mass.
D)maritime polar air mass.

Question 34

Why is mountainous terrain a poor source region for air masses?

Question 35

List two main characteristics of air mass source regions.

Question 36

________ air masses can form over the southwestern United States in summer,and are typically hot and dry.

Question 37

Continental polar air masses that form in summer are

A)less humid than winter cP air masses.
B)colder than winter cP air masses.
C)more likely to stay at higher latitudes than winter cP air masses.
D)less cloudy than winter cP air masses.

Question 38

In North America,cP masses are most likely to travel

A)east.
B)west.
C)north.
D)south.

Question 39

Which air mass is the driest?

A)mP
B)mT
C)cT
D)cA

Question 40

The ________ air mass forms off the Mexican High Plateau and impacts the southwestern part of the United States.

A)Maritime Tropical
B)Maritime Polar
C)Arctic
D)Continental Tropical

Question 41

Source regions for wintertime cP air masses receive little solar radiation at the surface due to

A)low sun angles.
B)high albedo.
C)low sun angle and high albedo.
D)low albedo.

Question 42

The air masses that approach the west coast of North America

A)usually began their lives as mP air.
B)usually gained moisture from the Japan current.
C)usually began their journey from somewhere near the Hawaiian Islands.
D)have the greatest influence on the California coast in summer.

Question 43

During winter,________ air masses are associated with poor air quality in urban areas because cold conditions lead to increased consumption of heating fuel.

A)cP
B)cT
C)mP
D)mT

Question 44

cT air masses usually form

A)in summer.
B)in high-latitude areas.
C)in moderately cool areas.
D)large quantities of rain-producing clouds.

Question 45

mP air masses

A)are colder than cP masses.
B)are drier than cP masses.
C)can produce northeasters on the Atlantic Coast of North America.
D)rarely affect North America.

Question 46

Which air mass is responsible for bringing virtually all of the moisture that impacts the United States east of the Rocky Mountains?

A)Continental Polar
B)Continental Tropical
C)Maritime Polar
D)Maritime Tropical

Question 47

mT air masses

A)typically develop over moderately cool waters.
B)are stable at their surfaces.
C)do not affect the southwestern United States.
D)often spawn thunderstorms.

Question 48

Most of the air masses in the central part of the United States are either

A)maritime polar or continental polar.
B)maritime polar or maritime tropical.
C)continental polar or maritime tropical.
D)continental tropical and maritime polar.

Question 49

________ air masses are ideal for the development of clouds and precipitation.

A)mP
B)mT
C)cP
D)cA

Question 50

In North America,mT masses from the Gulf of Mexico are most likely to travel

A)east.
B)southwest.
C)north.
D)south.

Question 51

When mT air flows inland from the Gulf of Mexico,it

A)results in long-lasting storms characterized by steady but light rainfall.
B)usually veers west toward the Rocky Mountains.
C)undergoes an increase in the temperature lapse rate.
D)loses heat to the land surface.

Question 52

As cP air moves south from Canada to near the Gulf of Mexico,the largest drop in temperature will occur at

A)the U.S.-Canadian border.
B)Minneapolis.
C)Saint Louis.
D)Birmingham.

Question 53

Maritime tropical masses reach North America from all of the following areas except

A)the northern Pacific.
B)the eastern Pacific.
C)the Gulf of Mexico.
D)the Middle Atlantic.

Question 54

After passing over a series of mountain ranges,maritime polar air becomes

A)warmer.
B)colder.
C)more moist.
D)drier.

Question 55

Which of the following air masses is associated with the "Arizona monsoon"?

A)mT
B)mP
C)cT
D)cP

Question 56

The combination of dry air and stable conditions ensures that few if any clouds will form over a ________ source region.

A)mT
B)mP
C)cT
D)cP

Question 57

The Pineapple express

A)lowers the snow line in Southern California.
B)brings more rain to Northern California than to Southern California.
C)originates in the South Pacific.
D)is most prominent during El Niño years.

Question 58

This region of the United States is most greatly affected by mT air masses.

A)northeast
B)southeast
C)midwest
D)northwest

Question 59

An mT air mass moving toward San Diego from the eastern tropical Pacific

A)is forced to rise by mountains.
B)must cross a desert.
C)is modified by the cold California current.
D)becomes warmer and more humid.

Question 60

Northeasters

A)are associated with anticyclones.
B)are associated with warm winds.
C)are rarest in winter and early spring.
D)often bring heavy snowfall.

Question 61

Which of the following fronts do not separate tropical from polar air masses?

A)cold
B)warm
C)stationary
D)occluded

Question 62

There are ________ primary types of fronts.

A)one
B)two
C)three
D)four

Question 63

How does a northeaster form and what types of weather does it typically bring to the East Coast?

Question 64

The boundary between a warm air mass moving into a cold air mass is called a(n)

A)warm front.
B)cold front.
C)stationary front.
D)occluded front.

Question 65

What is the Pineapple express and what effect does it have on California weather?

Question 66

The ________ is a boundary that forms mainly in the southern Plains and produces severe thunderstorms and tornadoes.

A)squall line
B)pressure jump line
C)gravity wave line
D)dry line

Question 67

Air masses that form over northern Siberia are most likely to be ________ air masses.

Question 68

The boundary between two air masses is called a(n)

A)dividing line.
B)squall line.
C)instability line.
D)front.

Question 69

Which air mass is likely to have the highest dew point?

A)mP
B)mT
C)cP
D)cA

Question 70

A cP air mass moves southward from Chicago to New Orleans.Which of the following is most likely to occur?

A)The air mass would become drier.
B)The air mass would moderate.
C)The sea level pressure would rise.
D)The wind would blow from the south.

Question 71

This type of front moves very slowly,if at all: ________ front.

Question 72

Which air mass is associated with the highest sea level pressure?

A)mP
B)mT
C)cP
D)cT

Question 73

Describe the formation of the mP air masses that brings most of the moisture to the west coast of North America.

Question 74

Give the typical characteristics of mT air masses and describe the nature of the precipitation it would typically bring to the southeastern United States.

Question 75

________ air masses are colder than continental polar air masses.

Question 76

This type of air mass is responsible for much of the precipitation along the coast of western North America: ________.

Question 77

Would you expect to find a cA air mass in the Southern Hemisphere? Explain.

Question 78

Compare and contrast winter cP air masses and summer cP air masses in terms of their formation conditions,their typical movements,and their temperature and moisture characteristics.

Question 79

An mT air mass from the Gulf of Mexico moves northward from New Orleans,Louisiana to Chicago,Illinois.Which of the following is most likely to occur?

A)The air mass would become drier.
B)The sea level pressure would rise.
C)The air mass would become more humid.
D)The temperature would fall quickly.

Question 80

Maritime polar air masses are similar to these types of air masses,except they are more moderate in both temperature and dryness.

A)mT
B)cP
C)cT
D)none of these