Chapter 10: Thunderstorms and Tornadoes 1) Prediction success ...

Chapter 10: Thunderstorms and Tornadoes
1) Prediction success and observation of severe thunderstorms and tornadoes by the
National Weather Service is limited because
A) wind speeds are too fast to measure
B) weather stations are widely spaced compared to the size of the storm
C) lightning activity prevents accurate radar detection
D) observers are not always well trained
E) the structure of thunderstorms is not well known
2) The Fujita Intensity Scale (F-scale) is applied to:
A) lightning B) typhoons C) thunderstorms D) tornadoes
3) The circulation in the immediate vicinity of a thunderstorm is:
A) cyclonic
B) variable and gusty
C) anticyclonic
D) both a and c
E) none of these
4) This type of cloud brings thunderstorms:
A) cumulus
B) stratocumulus
C) altostratus
D) cumulonimbus
E) nimbostratus
5) At what time of day is an air-mass thunderstorm more likely to develop?
A) midafternoon
B) midnight
C) midmorning
D) these storms are equally common at all of these times
6) The formation of tornadoes is associated with:
A) middle-latitude cyclones B) severe thunderstorms
C) cold fronts D) all of the above
7) Thunderstorms can be associated with these weather activities:
A) hurricanes
B) cyclones
C) tornadoes
D) a, b, and c
E) none of these

8) The terms leader, flash, and stroke are used when describing:
A) a tornado
B) the passage of a hurricane
C) squall line formation
D) the stages of a thunderstorm
E) none of these
9) Conventional radar measures
A) raindrop motion
B) rainfall intensity
C) cloud droplet numbers
D) raindrop and snowflake motion
E) raindrop size
10) Tornadoes most often move toward what direction?
A) southeast B) west C) northwest D) southwest E) northeast
11) Thunderstorm tops most likely occur
A) in the mesosphere B) in the lower troposphere
C) near the tropopause D) in the middle stratosphere
12) Doppler radars
A) show the motion of precipitation particles
B) have much greater range than conventional radars
C) detect lightning strokes
D) detect condensation nuclei
E) show the motion of air in clear areas
13) Thunderstorms and large cumulus clouds are characteristic of
A) isothermal lapse rates
B) stable air
C) all polar air masses
D) unstable air
E) all warm fronts
14) Which of the following is likely during the mature stage of a thunderstorm?
A) lightning
B) heavy precipitation
C) gusty winds
D) a, b, and c
E) none of these
15) Which of the numbers listed below best represents the percentage of thunderstorms
that produce tornadoes?
A) about 10 percent B) less than 1 percent
C) slightly more than 50 percent D) nearly 25 percent

16) A tornado is a small, very intense example of the
A) geostrophic wind
B) jet stream
C) cyclone
D) anticyclone
E) coriolis effect
17) Which of the following statements is not true of tornadoes?
A) generally move from the southwest toward the northeast
B) usually occur along the warm front of a midlatitude cyclone
C) most common in the Midwest and Great Plains
D) associated with cumulonimbus clouds
E) occur most frequently in the spring of the year
18) Why do most tornadoes in the central U.S. occur during the spring months?
A) surface air is most humid
B) air-mass contrasts are greatest
C) divergence of air aloft is greatest
D) solar energy is a maximum
E) upper-air temperatures are warmest
19) Downdrafts and updrafts found side by side relate to the ________ in the development
of a thunderstorm.
A) mature stage B) dissipating stage C) cumulus stage
20) The approximate lifetime of an individual thunderstorm cell is about
A) 4 - 8 hours
B) 1 day
C) 12 hours
D) 1 hour or less
E) 15 minutes
21) Which type of lightning is least likely?
A) cloud-to-cloud
B) within the same cloud
C) cloud-to-earth
D) all three are about equally likely
E) b and c are about equally the least likely
22) The diameter of a typical tornado funnel cloud would be
A) 4000 meters
B) 1000 meters
C) 50 meters
D) 200 meters
E) 2500 meters

23) Of the following states, which is struck by the largest number of tornadoes?
A) North Dakota
B) North Carolina
C) New Mexico
D) Ohio
E) Oklahoma
24) Which of the following should have the steepest pressure gradient?
A) hurricane
B) middle-latitude cyclone
C) tornado
D) a, b and c should have equally steep pressure gradients
E) both a and c have equally steep pressure gradients
25) The gust front occurs
A) during the development of thunderstorm clouds
B) at the leading edge of a thunderstorm downdraft
C) on the lee shore of the Great Lakes
D) near the anvil part of a thunderstorm cloud
26) Tornadoes and midlatitude cyclones are similar in that:
A) both form in the trade-wind belt
B) both are most common and well-developed in the winter season
C) both are areas of low pressure
D) both have conspicuous surface fronts
27) Updrafts dominance relate to the ________ in the development of a thunderstorm.
A) dissipating stage B) cumulus stage C) mature stage
28) Which of these is important to the formation of lightning in a growing cumulus cloud?
A) absorption of solar cosmic rays
B) formation of ice particles
C) formation of mammatus cloud
D) strong vertical currents
E) both b) and d)
29) In the development of a thunderstorm, sharp and cool gusts beginning at the surface are
characteristic in the ________.
A) mature stage B) cumulus stage C) dissipating stage
30) The greatest proportion of thunderstorms occurs in the
A) subarctic regions
B) middle latitudes
C) tropics
D) polar regions
E) subtropics

31) What does the term mesocyclone refer to in reference to a tornado?
A) a false-alarm tornado warning
B) the rotation motion of the parent thunderstorm
C) a high-altitude tornado
D) a very large tornado
E) none of the above
32) "Heat lightning":
A) is actually a display of the northern lights
B) occurs more than 20 kilometers from the person observing it
C) is also called "ball lightning"
D) is brighter than ordinary lightning
33) Why is strong heating of the ground by the sun associated with thunderstorms?
A) increases the pressure gradient
B) increases the wind speed
C) leads to greater instability
D) reduces the dew point
E) reduces the relative humidity
34) What causes the dissipating stage of a thunderstorm?
A) spreading downdraft cuts off air inflow
B) loss of radiant energy from cloud top
C) release of latent heat within the cloud
D) converging winds aloft
E) converging surface winds
35) Over the last 20 years, which of these has caused the fewest weather related deaths in
the U.S.?
A) hurricanes B) lightning C) floods D) tornadoes
36) An air mass thunderstorm is most intense during the ________ stage.
A) cumulus B) multicell C) mature D) dissipating
37) Why is very humid air near the surface a necessary ingredient for severe thunderstorms?
A) more latent heat is then available as energy for the storm
B) high humidity makes the air more dense
C) high humidity strengthens the cold front
D) high humidity makes the rising air cool more rapidly
E) lapse rates are larger in humid air
38) Why are thunderstorms most likely to occur in the afternoon and early evening?
A) upper-level winds are too fast at night and in morning
B) water-vapor contents are too low at night
C) it takes all day for them to mature
D) atmosphere is most unstable at that time
E) lower atmosphere is too unstable in the morning

39) If you see lightning and then hear the associated thunder 10 seconds later, the lightning
flash was about ________ mile(s) away.
A) three B) one C) five D) four E) two
40) In which of the following places are thunderstorms most common?
A) the occurrence of thunderstorms at all of these places should be about the same
B) west of Hudson Bay (Canada)
C) central Nevada
D) southern Mississippi
E) northern Wisconsin
41) Downdrafts totally dominate the ________ in the development of a thunderstorm.
A) dissipating stage B) cumulus stage C) mature stage
42) Tornadoes are most frequent during the:
A) April-June period
B) October-December period
C) January-March period
D) July-August period
E) month of September
TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false.
43) Squall lines are easily recognized because of their unique nimbostratus clouds.
44) Lightning only occurs under the central part of a thunderstorm cloud.
45) The airflow pattern aloft is not usually related to severe thunderstorm development.
46) Large hail is associated with cold-front thunderstorms.
47) Weak tornadoes (F0-F1) are responsible for the majority of tornado deaths because they
are far more common than stronger tornadoes (F2 and above).
48) The primary force causing the fast winds of a tornado is electrical.
49) On average, tornadoes kill more people every year in the United States than any other
severe weather phenomenon.
50) The anvil top of a thunderstorm often marks the beginning of the stratosphere.
51) Lightning always occurs between a cloud and the ground.
52) Thunder generates lightning.
53) A mesocyclone often precedes tornado development.
54) Doppler radar can now provide adequate warning of impending tornadoes at least 95
percent of the time.

55) Tornadoes form in association with tall cumulonimbus clouds.
56) Most precipitation from thunderstorms originates through the collision-coalescence
process.
57) A tornado warning is issued by the National Weather Service when conditions are
favorable for tornado development.
58) Lightning results in a net flow of electrons from the ground to the cloud.
59) If a severe thunderstorm produces large hail, it will not produce a tornado.
60) Entrainment refers to the tendency of thunderstorms to form in a line-like pattern or
sequence.
61) A thunderstorm's direction of movement over the ground is determined by the gust
front.
62) The central United States sees more tornadoes than any other region in the world.
63) Thunderstorms are not always associated with cyclonic activity.
64) Destruction caused by a tornado is primarily due to the large pressure drop as the funnel
passes over.
65) A tornado watch is issued by the National Weather Service after a tornado has been
sighted in an area.
66) Divergence in the upper-level jet stream hinders the formation of severe thunderstorms.
67) When tornadoes develop it is usually in association with air-mass thunderstorms.
68) Radar detects a thunderstorm by measuring the electrical discharges within the cloud.
69) Temperature inversions (stable layers) in air layers above the ground can contribute to
thunderstorm development.
70) Doppler radar can detect motion directly.
71) About 50 percent of North American tornadoes are classified as violent (F4-F5).