Meteorology - Chapter 10 - Thunderstorms and Tornadoes
7) About what percent of thunderstorms in the United States become severe?
A) 10%
68) Why do most tornadoes in the central U.S. occur during the spring months?
A) Air-mass contrasts are greatest.
13) Why are air mass thunderstorms most likely to occur in the midafternoon?
A) Atmosphere is most unstable at that time.
8) Which of the following U.S. states experiences the most thunderstorms each year?
A) Florida
28) What key change does wind shear promote in a thunderstorm that helps extend its life span?
A) It causes the storm to become tilted.
34) Where would you expect to find precipitation occurring in this thunderstorm?
A) Letter A
80) The NWS branch charged specially with providing forecasts and watches for severe weather is called the:
A) Storm Prediction Center (SPC).
6) ________ is defined as a significant change in wind speed and/or wind direction with increasing height above the surface.
A) Wind shear
44) Which of the following is the key ingredient required in order to transform ordinary thunderstorms into mesoscale convective complexes?
A) a strong low-level flow of warm, moist air
23) A microburst is:
A) another name for a downburst.
83) Dual-polarization technology as allowed Doppler Radar to:
A) better identify the type, size, intensity, and location of precipitation.
20) Updrafts dominate the cumulonimbus cloud during the ________ in the life cycle of an air mass thunderstorm.
A) cumulus stage
15) Generally there are three stages involved in the development of ordinary (or air mass) thunderstorms. They are:
A) cumulus stage, mature stage, and dissipating stage.
21) Downdrafts totally dominate the ________ of an air mass thunderstorm.
A) dissipating stage
40) The greatest number of deaths associated with thunderstorms result from:
A) flash flooding.
56) The total discharge of lightning is made up of several rapid strokes and is known as the:
A) flash.
11) Ordinary, or air-mass, thunderstorms usually form in association with ________ air masses.
A) mT
32) All of the following can form in association with the gust front EXCEPT:
A) mesocyclones
14) At what time of day is an air-mass thunderstorm more likely to develop?
A) midafternoon
27) Any of the following conditions can cause a thunderstorm to be classified as severe EXCEPT:
A) roll clouds preceding the gust front
58) During the formation of a lightning strike, a ________ is emitted from the surface and connects with the channel mid-air in order to complete the path for electrons to travel into the ground.
A) streamer
43) In the United States, a mesoscale convective complex is most likely to develop in:
A) the Great Plains.
25) An air mass thunderstorm rarely lives long enough to create very severe weather because:
A) the downdrafts quickly become strong enough to stop the updraft and influx of moisture to the storm.
47) Drylines are capable of producing thunderstorms because:
A) the dry air mass forces the moist air mass to rise.
37) The feature identified by Letter D is:
A) the gust front.
75) The Enhanced Fujita scale is based on:
A) the level of damage caused by a tornado.
51) Which of the following thunderstorm features will typically only develop if vertical directional shear is present?
A) the mesocyclone
16) What is entrainment?
A) the process of cool, dry air being pulled into a thunderstorm by the downdraft
52) What does the term mesocyclone refer to?
A) the rotation of the updraft in the parent thunderstorm
77) Which association is incorrect?
A) tornado watch — a tornado has been sighted on the ground
78) The Enhanced -Fujita Intensity Scale (EF-scale) is applied to:
A) tornadoes.
64) Multiple-vortex tornadoes help explain:
A) why one building is destroyed and the one next to it is untouched.
100) Cloud-to-ground lightning results in a flow of electrons from the ground to the cloud.
Answer: FALSE
86) Most precipitation from thunderstorms originates through the collision-coalescence process.
Answer: FALSE
89) Entrainment refers to the tendency of thunderstorms to form in a line-like pattern or sequence.
Answer: FALSE
90) Severe thunderstorm development occurs independently from the air flow aloft.
Answer: FALSE
92) On average, tornadoes kill more people every year in the United States than any other severe weather phenomenon.
Answer: FALSE
93) Squall lines are easily recognized because of their unique nimbostratus clouds.
Answer: FALSE
95) When tornadoes develop it is usually in association with air-mass thunderstorms.
Answer: FALSE
97) It is generally considered safe to talk on the phone during a lightning storm, as long as it is a corded telephone.
Answer: FALSE
98) Lightning only occurs under the central part of a thunderstorm cloud.
Answer: FALSE
99) Lightning always occurs between a cloud and the ground.
Answer: FALSE
84) The anvil top of a thunderstorm often marks the beginning of the stratosphere.
Answer: TRUE
85) During the dissipating stage of a thunderstorm, the downdraft is stronger than the updraft.
Answer: TRUE
87) An airplane flown by an untrained pilot is likely to crash if it flies through a downburst.
Answer: TRUE
88) Mountainous regions, such as the Rockies in the West and the Appalachians in the East, experience a greater number of air-mass thunderstorms than do the Plains states.
Answer: TRUE
91) Large hail is generally associated only with severe thunderstorms.
Answer: TRUE
94) A squall line with severe thunderstorms can form along a boundary called a dryline, a narrow zone along which there is an abrupt change in moisture.
Answer: TRUE
96) Temperature inversions (stable layers) in air layers above the ground can enhance thunderstorm development.
Answer: TRUE
71) The diameter of a typical tornado funnel cloud would be:
B) 150 - 600 meters.
63) Because of the tremendous pressure gradient associated with a strong tornado, maximum winds approach ________ miles per hour.
B) 300
57) Which of the following demonstrates the correct order of the phases involved in a lightning stroke?
B) Charge separation, step leaders, return stroke, flow of negative charge into ground, dart leader
73) Why do most tornadoes tend to travel in the same general direction?
B) They generally occur in a zone of southwest winds.
42) More than half of all the flash-flood deaths occurring in the United States:
B) are auto related.
79) Severe convective outlooks:
B) are issued several times daily and describe the types, coverage, and likelihood of severe weather expected across the United States.
9) In which of the following places are thunderstorms most common?
B) central Florida
54) Which type of lightning is least likely?
B) cloud-to-Earth
22) Extreme evaporative cooling can sometimes produce explosions of straight-line winds called:
B) down bursts.
41) Hurricanes and thunderstorms can sometimes cause rapidly rising local floods that are short-lived but high volume. These are called:
B) flash floods.
18) Downdrafts and updrafts found side by side occur during the ________ in the life cycle of an air mass thunderstorm.
B) mature stage
33) The leading edge of a gust front is frequently associated with:
B) the development of a new cumulonimbus cloud.
53) Because air is a poor conductor of electricity, what must be true before lightning can strike?
B) the electrical potential between the regions of opposite charges must be very high.
29) An overshooting top means that:
B) the thunderstorm has very strong updrafts causing the cloud to grow into the stratosphere.
67) Which of the following statements is not true of tornadoes?
B) usually occur along the warm front of a midlatitude cyclone
2) At any given time, about how many thunderstorms are in progress on Earth?
C) 2,000
69) Tornadoes are most frequent during the:
C) April-June period.
76) A tornado that does devastating damage and has estimated wind speeds of 300 km/hr (186 mph) would be ranked as an:
C) EF-4.
39) Which feature of the thunderstorm is created by the gust front?
C) Letter C
38) Where in the thunderstorm would you be most likely to find mammatus clouds?
C) Letter E
70) Of the following states, which is struck by the largest number of tornadoes?
C) Oklahoma
45) ________ are relatively narrow, elongated bands of thunderstorms that develop in the warm sector of a middle-latitude cyclone, usually in advance of a cold front.
C) Squall lines
35) The feature identified by Letter F is:
C) an overshooting top.
30) The gust front occurs:
C) at the leading edge of a thunderstorm downdraft.
49) Mesoscale convective complexes:
C) begin as air mass thunderstorms that form in the afternoon.
19) In the development of a thunderstorm, sharp and cool gusts beginning at the surface are characteristic in the:
C) mature stage.
72) Tornadoes most often move toward what direction?
C) northeast
26) Multicell thunderstorms occur when:
C) thunderstorms in various stages of development are clustered together.
61) Which of the following should have the steepest pressure gradient?
C) tornado
4) Thunderstorms and large cumulonimbus clouds are characteristic of:
C) unstable air.
3) Thunderstorms form when ________, humid air rises in a(n) ________ environment.
C) warm; unstable or conditionally unstable
1) About how many thunderstorms take place on Earth every day?
D) 45,000
65) Which of the following statements best describes multiple-vortex tornadoes?
D) Multiple suction vortices circulate around a single tornadic center.
74) What is the deadliest tornado on record in the United States?
D) The Tri-State tornado of 1925
46) A squall line is most likely to develop where?
D) along a dryline in the warm sector of a mid-latitude cyclone
66) Which of the numbers listed below best represents the percentage of thunderstorms that produce tornadoes?
D) fewer than 1 percent
36) The feature identified by Letter F is most likely:
D) in the stratosphere.
59) "Heat lightning":
D) is regular lightning occurring more than 20 kilometers from the person observing it.
55) The terms leader, flash, and stroke are used when describing:
D) lightning.
17) An air mass thunderstorm is most intense during the ________ stage.
D) mature
5) Thunderstorm tops most likely occur:
D) near the tropopause.
81) Doppler radar measures:
D) rainfall intensity and motion within the storm.
48) Some of the most dangerous weather is produced by a type of thunderstorm called a(n):
D) supercell.
31) A roll cloud forms in association with which other common thunderstorm feature?
D) the gust front
50) Why is very humid air near the surface a necessary ingredient for severe thunderstorms?
E) More latent heat is then available as energy for the storm.
62) A tornado is also sometimes known as a:
E) cyclone.
12) Why is strong heating of the ground by the Sun associated with thunderstorms?
E) leads to greater instability
82) Doppler radars:
E) show the motion of precipitation particles.
24) What causes the dissipating stage of a thunderstorm?
E) spreading downdraft cuts off air inflow
10) Thunderstorms occur year-round in the:
E) tropics.
60) If you see lightning and then hear the associated thunder 10 seconds later, the lightning flash was about ________ mile(s) away.
E) two
