Deck 11: Air Masses and Fronts

Question 1

"Back-door" cold fronts are most common in the Pacific Northwest of the United States.

Answer 1

False

Question 2

In an exceptionally cold winter during which the Great Lakes were entirely covered by ice, lake effect snows would be expected in extremely high frequency and intensity.

Answer 2

False

Question 3

Cold fronts are colored purple on a weather map.

Answer 3

False

Question 4

Along the boundary between continental polar and maritime tropical air masses, widespread precipitation and storminess are often found.

Question 5

The "average" speed of a cold front is about half that of an "average" warm front.

Question 6

Drylines may be detected by Doppler radar when insects and insect-eating birds congregate along them. On the radar screen, the echo from insects and birds shows up as a thin line, called a fine line.

Question 7

A good source region for an air mass would be ____.

A)mountains with deep valleys and strong surface winds
B)generally flat areas of uniform composition with light surface winds
C)hilly with deep valleys and light winds
D)generally flat area of uniform composition with strong surface winds
E)mountainous areas with low surface pressure

Question 8

Freezing rain more commonly occurs with warm fronts than with cold fronts.

Question 9

Continental arctic and continental polar air masses can be difficult to distinguish, especially when the arctic air mass has traveled over warmer terrain.

Question 10

In the Central Plains of the United States, continental polar air is welcome in both winter and summer.

Question 11

The origin of cP and cA air masses that enter the United States is

A)Northern Siberia.
B)the Northern Atlantic Ocean.
C)Antarctica.
D)Northern Canada and Alaska.
E)the Eastern Pacific Ocean.

Question 12

Fronts are associated with high pressure.

Question 13

At the surface, occluded fronts are always followed by colder air.

Question 14

On a colored weather map, a stationary front is drawn as an alternating red and blue line. Red semicircles face toward colder air on the red line and blue triangles point toward warmer air on the blue line.

Question 15

A good air mass source region is generally flat and of uniform composition with light surface winds.

Question 16

Continental tropical (cT)air masses are responsible for the heat waves of summer in the western United States.

Question 17

Drylines are most frequently observed in the western half of Texas, Oklahoma, and Kansas, especially during spring and early summer. In these locations, drylines tend to move eastward during the day, then westward toward evening.

Question 18

Occluded fronts are often associated with a broad band of precipitation.

Question 19

The central United States is a very good air mass source region.

Question 20

Maritime tropical (mT)air masses are responsible for daily afternoon thunderstorms along the Gulf Coast.

Question 21

Which air mass would show the most dramatic change in both temperature and moisture content as it moves over a large body of very warm water?

A)cT in summer
B)cP in winter
C)mP in winter
D)mT in summer
E)mA in winter

Question 22

The designation for a cool, moist air mass is ____.

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

Question 23

One would expect a cP air mass to be

A)cold and dry.
B)cold and moist.
C)warm and dry.
D)warm and moist.
E)temperate and dry.

Question 24

The lake effect occurs when a(n)____ air mass moves over a ____ body of water.

A)mT; cold
B)mT; warm
C)cA; cold
D)cP; cold
E)cP; warm

Question 25

Clear sunny days with very cold nights would be associated with what type of air mass?

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

Question 26

During the spring, which air mass would most likely bring record-breaking high temperatures to the eastern half of the United States?

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

Question 27

What type of air mass would be responsible for persistent cold, damp weather with drizzle along the east coast of North America?

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

Question 28

What type of air mass would be responsible for refreshing cool, dry breezes after a long summer hot spell in the Central Plains?

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

Question 29

Continental polar (cP)and continental Arctic (cA)air masses

A)both originate over polar oceans.
B)form in summer only.
C)originate over the ice- and snow-covered regions of the Arctic, northern Canada, and Alaska where long, clear nights allow for strong radiational cooling of the surface.
D)bring strong thunderstorms.
E)produce wet weather and temperatures around the freezing point.

Question 30

Lake-effect snows are best developed around the Great Lakes during ____.

A)early spring when moist, tropical air moves over the frozen lakes
B)late fall and early winter when cold, dry polar air moves over the relatively warm water
C)late fall and early winter when moist, polar air sweeps in from the east
D)middle winter when the unseasonably warm air mass moves over the cold water
E)late winter after prolonged periods of cold weather

Question 31

What type of air mass would be responsible for hot, muggy summer weather in the eastern half of the United States?

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

Question 32

The Pineapple Express is an example of a relatively narrow channel of very most air known as a(an)____.

A)occluded front
B)back-door front
C)upper-level trough
D)atmospheric river
E)dryline

Question 33

An air mass is characterized by similar properties of ____ and ____ in any horizontal direction.

A)temperature; pressure
B)pressure; humidity
C)winds; humidity
D)temperature; humidity
E)pressure; winds

Question 34

Wintertime mP air masses are less common along the Atlantic coast of North America than along the Pacific coast mainly because the ____.

A)water is colder along the Pacific coast
B)prevailing winds aloft are westerly
C)source region for mP air on the Atlantic coast is Western Europe
D)water is warmer along the Atlantic coast
E)land is colder along the Atlantic coast

Question 35

The air mass with the highest actual water vapor content is

A)mT.
B)cT.
C)mP.
D)cP.
E)cA.

Question 36

These air masses are warm and humid, and are responsible for the hot, muggy weather experienced by the eastern United States during the summer months. Which air masses are formed in regions where long, clear nights allow for strong radiational cooling of the surface?

A)cT
B)mT
C)cA
D)cP
E)cA

Question 37

Record-breaking low temperatures are associated with which air mass?

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

Question 38

Compared to an mP air mass, mT air is

A)warmer and windier.
B)warmer and moister.
C)colder and calmer.
D)colder and moister.
E)warmer and drier.

Question 39

The coldest of all air masses is ____.

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

Question 40

Which of the following statements is most plausible?

A)In winter, cP source regions have higher temperatures than mT source regions.
B)In summer, mP source regions have higher temperatures than cT source regions.
C)In winter, cA source regions have lower temperatures than cP source regions.
D)In summer, mT source regions have lower temperatures than mP source regions.
E)In spring and fall, mP source regions have higher temperatures than cT source regions.

Question 41

Squall lines most often form ahead of a ____.

A)cold front
B)warm front
C)cold-type occluded front
D)warm-type occluded front
E)stationary front

Question 42

A dryline is ____.

A)a stalled cold front
B)a stalled warm front
C)a dew point front
D)a boundary marking a strong horizontal change in atmospheric moisture
E)both a dew point front and a boundary marking a strong horizontal change in atmospheric moisture

Question 43

A "back-door" cold front best describes which of the following situations?

A)A cold front moving into Washington state from the Pacific Ocean
B)A cold front moving into the desert southwest from Northern Mexico
C)A cold front that moves into New England from the Atlantic Ocean
D)A cold front that moves in a clockwise direction around a low-pressure center
E)A cold front that originated over the Pacific Ocean.

Question 44

What type of weather front would likely be responsible for the following weather forecast? "Light rain and cold today with temperatures just above freezing. Southeasterly winds shifting to westerly tonight. Turning colder with rain becoming mixed with snow, then changing to snow."

A)Dryline
B)Warm front
C)Cold-type occluded front
D)Warm-type occluded front
E)Stationary front

Question 45

What type of weather front would likely be responsible for the following weather forecast? "Increasing high cloudiness and cold this morning. Clouds increasing and lowering this afternoon with a chance of snow or rain tonight. Precipitation ending tomorrow morning. Turning much warmer. Winds light easterly today becoming southeasterly tonight and southwesterly tomorrow."

A)Dryline
B)Warm front
C)Stationary front
D)Dryline
E)Cold-type occluded front

Question 46

The word frontogenesis on a weather map would mean that ____.

A)a front is in the process of dissipating
B)one front is about to overtake another front
C)a front is regenerating or strengthening
D)severe thunderstorms will form along a front
E)a front is approaching

Question 47

If either a cold front or a warm front stops moving, what does it become?

A)A stationary front
B)A dryline
C)A dew point front
D)An occluded front
E)An upper-air front

Question 48

After an occluded front passes, the winds are most likely to be ____.

A)variable
B)from the west or northwest
C)from the south or southeast
D)calm
E)from the east or northeast

Question 49

During the winter as you travel toward a warm front, the most likely sequence of weather you would experience is ____.

A)snow, freezing rain, hail, and sleet
B)rain, snow, sleet, freezing and rain
C)freezing rain, snow, sleet, and rain
D)snow, sleet, freezing rain, and rain
E)hail, sleet, freezing rain, and snow

Question 50

Before the passage of a cold front the pressure normally ____, and after the passage of a cold front the pressure normally ____.

A)drops; drops
B)drops; rises
C)rises; rises
D)rises; drops
E)does not change; drops

Question 51

A stationary front does not move because ____.

A)winds on both sides of the front are calm
B)the winds blow parallel to the front
C)the front is between high and low pressure
D)the winds blow against each other and are of equal strength
E)the winds blow perpendicular to the front

Question 52

At a warm front, the warm air ____.

A)rises and cools
B)rises and warms
C)sinks and cools
D)sinks and warms
E)does not move

Question 53

Occluded fronts may form when ____.

A)a cold front overtakes a warm front
B)a warm front overtakes a cold front
C)a cold front overtakes a squall line
D)overrunning occurs along a warm front
E)a cold front and warm front collide

Question 54

On a weather map, the transition zone between two air masses with sharply contrasting properties is marked by ____.

A)the letter "H"
B)the words "air mass weather"
C)a front
D)the letter "L"
E)a trough

Question 55

Lake-effect snows are snowstorms that form on the ____ side of a large lake.

A)north
B)east
C)upwind
D)west
E)downwind

Question 56

What type of weather front would likely be responsible for the following weather forecast? "Increasing cloudiness and warm today with the possibility of showers by this evening. Turning much colder tonight. Winds southwesterly becoming gusty and shifting to northwesterly by tonight."

A)Cold front
B)Warm front
C)Dryline
D)Stationary front
E)Warm-type occluded front

Question 57

Alternating lines of blue and red on a surface weather chart indicate a(n)____.

A)cold front
B)warm front
C)stationary front
D)occluded front
E)dryline

Question 58

The only indication on the station model of past weather conditions is the ____.

A)temperature
B)dew point
C)cloud cover
D)wind direction
E)pressure tendency

Question 59

A halo around the Sun or Moon indicates that rain may be on the way because the halo indicates a(n)

A)cold front may be approaching.
B)warm front may be approaching.
C)sharp drop in atmospheric pressure.
D)sudden rise in surface dew point temperature.
E)occluded front just passed.

Question 60

A true cold front on a weather map is always ____.

A)associated with precipitation
B)associated with a wind shift
C)followed by drier air
D)followed by cooler air
E)followed by moist air

Question 61

A line of active showers and thunderstorms that develops ahead of a fast-moving front is called a ____________________.

Question 62

What type of front will most likely pass the area when the weather forecaster states "Light rain and cold today, with temperatures just above freezing. Southeasterly winds shifting to westerly tonight. Turning colder with rain becoming heavy and possibly changing to snow."

A)Cold occluded front
B)Dryline
C)Warm occluded front
D)Warm front
E)Stationary front

Question 63

Regions where air masses originate are known as ____________________.

Question 64

Maritime polar air masses along the East Coast of the United States are usually ____________________ than those along the nation's West Coast.

Question 65

Along a dryline, the ____ may drop markedly.

A)wind direction
B)pressure
C)precipitation types
D)dew point temperatures
E)wind patterns

Question 66

Occluded fronts are colored ____________________ on a surface weather map.

Question 67

In some cases where a stationary front butts up against a mountain range winds blowing upslope can generate ____ (upslope precipitation)if there is enough moisture in the air.

A)heavy rain
B)heavy snow
C)hail
D)thunderstorms
E)light rain or snow

Question 68

Air masses are usually classified according to their ____ and ____.

A)pressure; humidity
B)wind direction; precipitation type
C)humidity; wind direction
D)temperature; pressure
E)temperature; humidity

Question 69

An mT air mass lying above a cold ground surface represents a(n)____________________ situation.

Question 70

A(n)____________________ is an extremely large body of air whose properties of temperature and humidity are fairly similar in any horizontal direction at any given altitude.

Question 71

The weather forecast "Increasing cloudiness and warm today, with the possibility of showers by evening. Turning much colder tonight. Winds southwesterly, becoming gusty and shifting to northwesterly by tonight" suggests that a(n)___________________ front is going to pass the area.

Question 72

Air masses are grouped into five general categories according to their ____________________.

Question 73

During the spring, on a warm, sunny day in Boston, Massachusetts, the wind shifts from southwesterly to northeasterly and the weather turns cold, damp, and overcast. This suggests that a "back-door" cold front approached Boston from the ____.

A)southeast
B)southwest
C)northeast
D)west
E)northwest

Question 74

Warm, humid, and a chance of thunderstorms is a typical weather pattern produced by an air mass designated as ____________________.

Question 75

A situation, where a cold front overtakes a slower moving warm front, then underrides and lifts off the ground both the warm front and the warm air mass, is called ____.

A)cold air trapping
B)"back-door" front
C)frontolysis
D)cold occluded front
E)cold air damming

Question 76

A front is the transition zone between two air masses of different ____.

A)dew point temperatures
B)cloud patterns
C)precipitation types
D)pressures
E)densities

Question 77

The weather forecast "Increasing high cloudiness and cold this morning. Clouds increasing and lowering this afternoon, with a chance of snow or rain tonight. Precipitation ending tomorrow morning. Turning much warmer. Winds light easterly today, becoming southeasterly tonight and southwesterly tomorrow" suggests that a(n)____________________ front is going to pass the area.

Question 78

You are in upstate New York and observe the wind shift from easterly to southerly. This shift in wind is accompanied by a sudden rise in both the air temperature and dew-point temperature. This means a(n)____ front passed.

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

Question 79

Air masses have both horizontal and vertical extent; consequently, the upward extension of a front is referred to as a(n)____________________ or ____________________.

Question 80

Barometric pressure usually falls with the approach of a(n)____________________ front or ____________________ front.