Deck 14: Thunderstorms

Question 1

Sinking air warms, yet the downdrafts in a thunderstorm are usually cold.

Answer 1

True

Question 2

Sonic booms are produced when an aircraft exceeds the speed of light at the altitude at which it is flying. The aircraft compresses the air, forming a shock wave that trails out as a cone behind the aircraft. Along the shock wave, the air pressure changes rapidly over a short distance. The rapid pressure change causes the distinct boom.

Answer 2

False

Question 3

In the valleys of central and southern California, dry, sinking air produces an inversion that inhibits the development of towering cumulus clouds during the summer. Hence, in these regions, thunderstorms are most frequent in winter and spring, particularly when cold, moist, conditionally unstable air aloft moves over moist, mild surface air.

Answer 3

True

Question 4

Lightning may occur from one cloud to another.

Question 5

Squall-line thunderstorms often form ahead of advancing cold fronts but seldom behind them.

Question 6

Lightning can travel in a number of directions, but it cannot travel from one cloud to another cloud.

Question 7

Even though the bright return stroke of lightning travels from the ground up to the cloud, it happens so quickly that our eyes cannot resolve the motion, and we see what appears to be a continuous bright flash of light.

Question 8

Lightning can shoot from the top of thunderstorms into the upper atmosphere.

Question 9

Thunderstorms are most common in the Great Plains states.

Question 10

One theory for the electrification of clouds involves supercooled cloud droplets.

Question 11

Left-moving supercell thunderstorms are uncommon in the Northern Hemisphere, yet are very common in the Southern Hemisphere.

Question 12

When a thunderstorm is located on the high plains east of the Rocky Mountains, a much larger portion of the storm will typically be located above the freezing level, so hail has a better chance of occurring.

Question 13

Large hail is more common in Kansas than in Florida.

Question 14

Although we often see thunderstorms forming where the surface air is quite warm and humid, they may also form when the surface air temperature is 10 degrees Celsius (50 degrees Fahrenheit)or even lower.

Question 15

One theory of cloud electrification states that during the formation of precipitation, regions of separate charge exist within tiny cloud droplets and larger precipitation particles. In the lower part of these particles we find negative charge, whereas in the upper part we find positive charge.

Question 16

Positive lightning has the potential to cause more damage because it generates a much higher current level and its flash lasts for a longer duration than negative lightning.

Question 17

In some thunderstorms, lightning is seen but thunder does not get produced by the lightning.

Question 18

All thunderstorms require ____.

A)hot air
B)divergence of the air aloft
C)lifting along some barrier such as a mountain or front
D)surface heating
E)rising air

Question 19

To be rated a severe thunderstorm by the National Weather Service, the storm has to have at least one of the following: large hail with a diameter of at least three-quarters of an inch, surface wind gusts of 40 knots or greater, or produces a tornado.

Question 20

Scientists understand with certainty how clouds are electrified.

Question 21

The most likely time for an ordinary thunderstorm to form is ____.

A)just after sunrise
B)just before sunrise
C)around midnight
D)late afternoon
E)at noon

Question 22

An ordinary thunderstorm is most intense during the ____ stage.

A)mature
B)multicell
C)cumulus
D)dissipating
E)growth

Question 23

Many flash floods, including the one that occurred in Colorado's Big Thompson Canyon, are the result of thunderstorms that _____.

A)contain no lightning
B)form in a dry air mass
C)move slowly
D)have weak or nonexistent downdrafts
E)lack the dissipating stage

Question 24

Distant lightning that is so far away you cannot hear the thunder is called ____.

A)sheet lightning
B)heat lightning
C)false lightning
D)St. Elmo's Fire
E)aurora lightning

Question 25

An ordinary thunderstorm ____.

A)does not produce lightning or thunder
B)has a tilted updraft and downdraft
C)is a scattered/an isolated storm and normally not severe
D)does not produce hail
E)does not produce precipitation

Question 26

Lightning that forms when either the lightning flash occurs inside a cloud or intervening clouds obscure the flash is known as ____.

A)St. Elmo's Fire
B)Ball lightning
C)Dry lightning
D)Sheet lightning
E)Heat lightning

Question 27

Which of the following is NOT a trigger needed to start air moving upward and thus causing thunderstorms?

A)Unequal heating at the surface
B)The lifting of air along shallow boundaries of converging surface winds
C)Large-scale uplift along mountain barriers
D)Diverging upper-level winds, coupled with converging surface winds and rising air
E)Cool air rising along a frontal zone

Question 28

The downdraft in an ordinary thunderstorm is created mainly by ____.

A)the melting of snow in the anvil
B)electrical attraction between the cloud and ground
C)the release of latent heat as water in the cloud freezes
D)evaporating raindrops that make the air cold and heavy
E)upper level wind motions

Question 29

Squall-line thunderstorms generally form _____.

A)along or ahead of a cold front
B)with a strong wave cyclone
C)behind a cold front
D)ahead of a warm front
E)along an occluded front

Question 30

Downdrafts tend to dominate during the ____ stage.

A)cumulus
B)dissipating
C)precipitating
D)developing
E)growth

Question 31

Squall lines generally do not form ____.

A)behind a cold front
B)when the air aloft develops waves downwind from a cold front
C)along a cold front
D)in the warm sector where warm, dry air meets warm, humid air
E)ahead of an advancing cold front

Question 32

Thunderstorms that produce tornadoes ____.

A)have very little cloud-to-ground lightning
B)have updraft velocities that exceed 100 miles per hour
C)have rotating updrafts
D)will not produce hail
E)do not exist

Question 33

The upper part of a thunderstorm cloud is normally ____ charged, and the middle and lower parts are ____.

A)negatively; neutral
B)negatively; positive
C)positively; positive
D)positively; negative
E)positively; neutral

Question 34

The wind shear associated with several major airline crashes is believed to have been caused by ____.

A)microbursts
B)dry lines
C)the jet stream
D)mesocyclones
E)the jet streak

Question 35

A small thunderstorm cloud with virga falling out of its base and blowing dust at the ground could warn of a severe hazard to an airplane because ____.

A)this could be the first indication of a tornado
B)it is likely that hail will soon begin to fall
C)this could indicate an intense downdraft or microburst
D)the airplane could be struck by lightning
E)a hurricane is close by

Question 36

The initial stage of an ordinary thunderstorm is the ____.

A)mature stage
B)dissipating stage
C)cumulus stage
D)multicell stage
E)primary stage

Question 37

Ordinary thunderstorms only last about one hour and begin to dissipate when ____.

A)lightning neutralizes all the electrical charge in the cloud
B)when all the precipitation particles in the cloud turn to ice
C)when the downdraft spreads throughout the cloud and cuts off the updraft
D)when solar heating at the ground begins to decrease
E)when clouds scatter due to the microbursts within the storm system

Question 38

Electrons ____.

A)are negatively charged
B)are positively charged
C)carry no charge
D)can carry either positive or negative charge
E)go back and forth between positive, negative, and neutral

Question 39

Thunderstorms typically form in the summertime during the warmest part of the day when the surface air is most unstable. In what part of the United States are thunderstorms most common in the winter and spring due to an inversion that inhibits the development of cumulus clouds?

A)In the valleys of Central and Southern California
B)In the Great Plains, bordering the Rockies
C)In Appalachia
D)In New England
E)In central Florida

Question 40

Which of the following is the least likely during the passage of a gust front?

A)Gusty winds
B)Rising surface pressures
C)Increase in temperatures
D)Enhanced updraft
E)Winds rapidly changing direction and speed

Question 41

If you see a lightning stroke and then, 15 seconds later, hear the thunder, the lightning is about ____ miles away.

A)45
B)15
C)5
D)3
E)1.5

Question 42

When thunderstorms are passing over the same area, they are ____.

A)recurring
B)practicing
C)revising
D)training
E)repeating

Question 43

When caught in a thunderstorm in an open field, the best thing to do is to ____.

A)run for cover under the nearest tree
B)lie down flat on the ground
C)crouch down as low as possible while minimizing contact with the ground
D)remove all metallic objects from your pockets
E)climb up onto a hill

Question 44

The greatest frequency of hailstorms in the United States is ____.

A)over the western Great Plains
B)along the Gulf coast
C)along the East Coast
D)in the Rocky Mountain region
E)along the West Coast

Question 45

This type of cloud is especially prevalent when the atmosphere is very stable near the base of a thunderstorm.

A)Shelf
B)Cumulus
C)Comma
D)Omega
E)Stratus

Question 46

When convection is strong and the updraft intense, the rising air may intrude into the stratosphere, producing ____.

A)a shelf cloud
B)straight-line winds
C)a roll cloud
D)a gust front
E)an overshooting tip

Question 47

Thunder is caused by ____.

A)the collision between two thunderstorms with opposite electrical charge
B)the rapid heating of air surrounding a lightning channel
C)the explosion that occurs when positive and negative charge collide and neutralize each other
D)turbulent wind motions inside the thunderstorm
E)microbursts within the atmosphere

Question 48

In what region in the United States do dryline thunderstorms most frequently form?

A)Washington, Oregon
B)Colorado, Utah, New Mexico
C)Pennsylvania, Maryland, Delaware
D)Texas, Kansas, Oklahoma
E)Tennessee, Louisiana

Question 49

A cloud-to-ground lightning discharge will sometimes appear to flicker. This is because ________.

A)you are able to see charges
B)you are barely able to distinguish separate return strokes
C)the bright light causes you to blink
D)of refraction caused by turbulent thunderstorm winds
E)your eyes momentarily get blinded by lightning

Question 50

Thunder will not occur ____.

A)without lightning
B)in wintertime thunderstorms
C)in thunderstorms over the ocean
D)when a thunderstorm is producing precipitation
E)in thunderstorms without precipitation

Question 51

The majority of lightning strikes occur within the cloud, whereas only about ____ percent or so occur between cloud and ground.

A)5
B)10
C)15
D)20
E)25

Question 52

An important principle in one of the theories of the electrification of clouds is that ____.

A)there is a net transfer of negative ions from a warmer object to a colder object
B)supercooled water is always negatively charged
C)ice crystals are always negatively charged
D)there is a net transfer of positive ions from a warmer object to a colder object
E)raindrops are always positively charged

Question 53

Ordinary cell thunderstorms most frequently form ____.

A)in the morning
B)at noon
C)in the afternoon
D)in the evening
E)at night

Question 54

In the United States, drylines can be associated with thunderstorms where and when?

A)In the Southeast during the winter
B)In the desert Southwest during summer and fall
C)In the upper Great Plains states during the summer
D)In Texas, Oklahoma, and Kansas during the spring and summer
E)Along the Pacific coast during the winter and spring

Question 55

Floods that develop rapidly with little or no advance warning are called ____ floods.

A)rapid
B)sudden
C)storm
D)thunderstorm
E)flash

Question 56

In the United States, winter thunderstorms often occur ____ when cold air aloft moves over the region.

A)in Hawaii
B)in the northeast
C)along the east coast
D)along the west coast
E)in the Gulf Coast region

Question 57

Supercell thunderstorms differ from ordinary cell (air mass)thunderstorms because ____.

A)the updraft in a supercell thunderstorm is short lasting and is stationary
B)ordinary thunderstorms do not produce hail
C)supercell thunderstorms produce precipitation
D)the supercell thunderstorm is greater in size
E)the updraft in a supercell thunderstorm is long lasting and rotates

Question 58

One of the most common times to experience a thunderstorm in parts of Iowa and Missouri is between ____ and ____.

A)early morning; noon
B)noon; late afternoon
C)midnight; dawn
D)late afternoon; evening
E)evening; midnight

Question 59

The highest frequency of thunderstorms in the United States occurs in ____.

A)California
B)Kansas
C)Colorado
D)Maine
E)Florida

Question 60

It is estimated that more than ____ thunderstorms occur each day throughout the world.

A)10,000
B)20,000
C)30,000
D)40,000
E)50,000

Question 61

When thunderstorms bring repeated heavy rain to a region for days or weeks, this phenomenon is known as ____________________ flooding.

Question 62

Typically, a lightning flash will have ____ leaders, each followed by a return stroke.

A)one or two
B)two or three
C)three or four
D)four or five
E)five or six

Question 63

The high winds behind a strong gust front are called ____________________ winds to distinguish them from the rotating winds of a tornado.

Question 64

Cloud-to-ground lightning begins within the cloud when the localized electric potential gradient exceeds ____ volts per meter along a path perhaps 50 m long.

A)300
B)3,000
C)30,000
D)300,000
E)3 million

Question 65

When a dart leader moving toward the ground deviates from the original path taken by the stepped leader, the lightning appears crooked. Lightning that takes on this shape is called ____ lightning.

A)ribbon
B)forked
C)crooked
D)bead
E)ball

Question 66

Positive lightning is more common with ____ thunderstorms.

A)ordinary cell
B)squall-line
C)multicell
D)supercell
E)mesoscale convective complex

Question 67

____________________ is a discharge of electricity, a giant spark, which usually occurs in mature thunderstorms.

Question 68

The lightning stroke can heat the air through which it travels to an incredible 30,000 degrees Celsius (54,000 degrees Fahrenheit), which is ____ times hotter than the surface of the Sun.

A)2
B)3
C)4
D)5
E)6

Question 69

Thunderstorms may form along or just east of a boundary called a(n)____________________, which represents a narrow zone where there is a sharp horizontal change in moisture.

Question 70

A sound occasionally mistaken for thunder is the ____________________.

Question 71

Where the cold downdraft reaches the surface, the air spreads out horizontally in all directions. The surface boundary that separates the advancing cooler air from the surrounding warmer air is called a ____________________.

Question 72

About ____ percent of all cloud-to-ground lightning is negative.

A)90
B)70
C)50
D)30
E)10

Question 73

For ____ to occur, separate regions containing opposite electrical charges must exist within a cumulonimbus cloud.

A)lightning
B)thunder
C)sonic boom
D)hail during a thunderstorm
E)tornadoes

Question 74

Sound travels ____________________ in warm air than in cold air.

Question 75

When damage associated with straight-line winds extends for several hundred kilometers along the path of a squall line, the storm is called a(n)____________________.

Question 76

A lightning flash consisting of many strokes usually lasts less than ____ second(s).

A)one
B)three
C)five
D)seven
E)nine

Question 77

____ lightning looks like a luminous sphere, often about the size of a football, that appears to float in the air or slowly dart about for several seconds

A)Ball
B)Bead
C)Ribbon
D)Forked
E)St. Elmo's

Question 78

Scattered thunderstorms (sometimes called "pop-up" or "popcorn" storms)that typically form on warm, humid days are often referred to as ____________________ thunderstorms or ____________________ thunderstorms.

Question 79

Thunderstorms are ____________________ storms that form with rising air.

Question 80

A thunderstorm is a storm containing ____________________ and ____________________.