Deck 11: Air Masses and Fronts

Question 1

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

Answer 1

False

Question 2

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

Answer 2

True

Question 3

​The weather forecast "Cool today with rain becoming heavy at times by this afternoon. Warmer tomorrow. Winds southeasterly becoming westerly by tomorrow morning." suggests that a warm occluded front is going to pass the area.

Answer 3

False

Question 4

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 5

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

Question 6

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 7

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

Question 8

Fronts are associated with high pressure​.

Question 9

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 10

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

Question 11

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

Question 12

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

Question 13

Occluded fronts are often associated with a broad band of precipitation

Question 14

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.

Question 15

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

Question 16

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

Question 17

Cold fronts are colored purple on a weather map.

Question 18

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

Question 19

The same cold front typically produces more rain over Kentucky than over western Kansas.

Question 20

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 21

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 22

The designation for a cool, moist air mass is

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

Question 23

The greatest contrast in both temperature and moisture will occur along the boundary separating which air masses?

A) ​cP and cT
B) ​mP and mT
C) ​mP and cT
D) ​mT and cP
E) ​cT and mT

Question 24

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 25

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 26

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 27

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 28

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 29

The coldest of all air masses is

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

Question 30

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 31

The air mass with the highest actual water vapor content is

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

Question 32

Which air masses are formed in regions where long, clear nights allow for strong radiational cooling of the surface?

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

Question 33

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 34

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 35

Record breaking low temperatures are associated with which air mass?

A) ​mT
B) ​mP
C) ​cP
D) ​cT
E) ​mA

Question 36

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 37

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 38

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 39

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 40

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 41

"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 42

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 43

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 44

In winter, which sequence of clouds would you most likely expect to observe as a warm front with precipitation approaches your location?

A) ​cirrus, nimbostratus, altostratus, and cumulonimbus
B) ​cirrus, cirrostratus, altostratus, and nimbostratus
C) ​cirrostratus, nimbostratus, altostratus, and fog
D) ​cirrus, cirrostratus, altostratus, and cumulonimbus
E) ​altostratus, cirrostratus, cirrus, and nimbostratus

Question 45

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 46

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 47

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 48

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 49

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 50

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 51

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 52

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 53

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 54

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 55

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 56

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 57

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 58

​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 59

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 60

An upper-air front involves downward motion of the

A) ​tropopause.
B) ​stratopause.
C) ​low-level jet.
D) ​both tropopause and low-level jet
E) ​both stratopause and low-level jet.

Question 61

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 62

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 63

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

Question 64

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

Question 65

A situation, where the cold, damp air is confined to the eastern side of mountains, is called​

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

Question 66

Regions where air masses originate are known as ____________________.​

Question 67

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

Question 68

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

Question 69

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 70

With slow-moving cold fronts, clouds and precipitation usually cover a broad area behind the front. When the ascending warm air is stable, ___________ clouds become the predominant cloud type.​

Question 71

​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)

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

Question 72

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 73

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 74

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 75

Occluded fronts are colored ____________________ on a surface weather map.​

Question 76

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 77

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

Question 78

Along a dryline, the ____ may drop markedly.

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

Question 79

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

Question 80

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