Chapter 14

25 July 2022
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All thunderstorms require:
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updraft, or rising air.
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The initial stage of an ordinary thunderstorm is the:
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cumulus stage.
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Ordinary thunderstorms only last about one hour and begin to dissipate when:
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downdraft spreads thru out the cloud and cuts off the updraft.
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An ordinary thunderstorm is a:
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scattered or isolated storm that isn't severe.
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Downdrafts spread throughout a thunderstorm during the ____ stage.
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dissipating.
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An ordinary thunderstorm is most intense during the ____ stage.
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mature.
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The most likely time for an ordinary thunderstorm to form is:
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afternoon.
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Severe thunderstorms are different from ordinary thunderstorms in that severe thunderstorms:
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tilted updraft in mature stage.
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A supercell storm is:
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enormous thunderstorm that lasts for several hours.
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Severe thunderstorms are capable of producing:
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ALL OF THE ABOVE.
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In a severe thunderstorm, hail may:
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ALL OF THE ABOVE.
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A Mesoscale Convective Complex is actually:
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rapidly rotating tornado cyclone inside a massive thunderstorm.
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Thunderstorms which produce tornadoes:
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have rotating updrafts.
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The downdraft in an ordinary thunderstorm is created mainly by:
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evaporating raindrops that make air cold and heavy.
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The cloud that forms along the leading edge of a gust front is called:
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Roll cloud.
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The leading edge of a thunderstorm's cold downdraft is known as a:
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gust front.
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The small area of high pressure created by the cold, heavy air of a thunderstorm downdraft is called:
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mesohigh
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Which of the following would you NOT expect to observe during the passage of a gust front?
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increase in air temp.
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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:
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it could indicate intense downright or microburst.
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The main difference between a downburst and a microburst is:
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size
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The wind shear associated with several major airline crashes is believed to have been caused by:
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mircoburst
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A relatively narrow downburst, less than 4 kilometers wide, is called a:
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microbursts.
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A group of thunderstorms which develop in a line one next to the other, each in a different stage of development, are called:
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multi cell thunderstorm.
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During the summer, what conditions prevail near the surface over the Great Plains that help a hailstone survive as ice all the way to the ground?
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cold, thick layer of moist air.
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Squall lines generally do not form:
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behind cold front (in front)
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A line of thunderstorms that forms ahead of an advancing cold front is called a:
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squall line
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On a surface weather map, which of the following marks the boundary where a warm, dry air mass encounters a warm, moist air mass?
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dry lines.
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Most squall line thunderstorms form:
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in advance of a cold front.
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HP supercell differs from a LP supercell based on the storm's:
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precipitation amount.
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Thunderstorms that move to the right of the winds aloft tend to:
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cut off the supply of humid air to thunderstorms to the north of them.
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Many flash floods, including those that occurred in Rapid City, South Dakota, and in Colorado's Big Thompson Canyon, are the result of thunderstorms that:
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move slowly.
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The region in the United States with the greatest annual frequency of hailstones is:
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midwest.
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Which figure comes closest to the estimated number of thunderstorms that occur each year throughout the world?
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100,000
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The greatest annual number of thunderstorms in the United States occurs in:
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florida.
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In the United States, dryline thunderstorms are most common in:
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Great plains.
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A sonic boom:
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loud explosive like sound caused by shockwaves eminiating from aircraft traveling at or above speed of sound.
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A discharge of electricity from or within a thunderstorm is called:
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lightening.
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The radio waves produced by lightning are called:
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sferics
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Lightning may occur:
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ALL THE ABOVE
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Lightning discharges within a cloud occur ____ cloud-to-ground lightning.
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more frequently.
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In cloud-to-ground lightning, the stepped leader travels ____ and the return stroke travels ____.
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downward ; upward.
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A second surge of electrons that proceeds from the base of a cloud toward the ground during cloud-to-ground lightning is called a:
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dart leader.
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The bluish halo that may appear above pointed objects underneath a thunderstorm is called:
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st elmo's
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St. Elmo's fire is most likely to occur:
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top of a dead tree.
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Distant lightning that is so far away you cannot hear the thunder is called:
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heat lightening.
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Electrons:
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negatively charged.
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The upper part of a thunderstorm cloud is normally ____ charged, and the middle and lower parts are ____ charged.
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+ ; -
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The electrification of a cumulonimbus cloud appears to involve:
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ALL THE ABOVE.
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An important principle in the electrification of a cumulonimbus cloud is that:
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Transfer of positive ions from a warmer object to colder objects.
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A cloud-to-ground lightning discharge will sometimes appear to flicker. This is because:
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you are able to distinguish separate return strokes.
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What would be the proper sequence of events in a lightning flash?
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??
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You a generally safe inside an automobile during a lighting storm because:
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metal car body will cary lightening currents around passenger inside.
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Which of the following is the most accurate description of the principle of a lightning rod?
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rod intercepts lightening and safely carries lightening current around object.
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Thunder is caused by:
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Rapid heating or air surrounding lightening channel.
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If you see a lightning stroke and then, 5 seconds later, hear the thunder, the lightning is about ____ miles away.
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3
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Thunder will not occur:
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without lightening.
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When caught in a thunderstorm in an open field, the best thing to do is to:
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crouch down as low as possible keep minimal distance from ground.
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A tornado vortex that does not touch the ground is called a:
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funnel cloud.
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A funnel cloud is composed primarily of:
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cloud droplets.
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Which of the following statements about tornadoes is correct?
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US has more tornado's than any other country in the world.
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The rotating updraft inside a severe thunderstorm is called a:
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mesocyclone.
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The small, rapidly rotating whirls that sometimes occur within a large tornado are called:
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Suction vorticies.
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A funnel cloud or tornado may develop from this rotating cloud that extends beneath a severe thunderstorm.
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wall cloud
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The funnel cloud characteristic of a tornado is principally formed by:
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condensation of water vapor in air drawn into low pressure core of tornado.
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In a typical tornado the winds are usually not much more than ____ miles per hour.
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110
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Most tornadoes move from:
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SW--> NE
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Which of the following factors is most important in determining the strength of a tornado?
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central pressure.
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If a tornado is rotating in a counterclockwise direction and moving toward the northeast, the strongest winds will be on its ____ side.
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South east.
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A typical diameter of a tornado would be:
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250m
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The so-called "Tornado Belt" of the United States is located:
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central plains.
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Different tornadoes spawned by the same thunderstorm are said to occur:
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families.
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The most frequent time of day for tornadoes to form is in the:
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late afternoon 4-9
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In the United States, tornadoes are most frequent during the ____, and least frequent during the ____.
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spring; winter.
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Which of the following regions would you expect to have the most tornadoes in the winter?
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southern gulf states.
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Tornadoes are usually observed:
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ahead of cold fronts.
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In an eastward moving thunderstorm, the most likely place for a tornado to develop is in the ____ part of the storm.
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southwest. (behind it.)
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In a region where severe thunderstorms with tornadoes are forming, one would not expect to observe:
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strong ridge with high pressure over region.
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Which below is the best indication that a severe thunderstorm is about to produce a tornado?
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a wall cloud.
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At home, when confronted with an approaching tornado, you should:
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seek shelter immediately.
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The Fujita scale pertains to:
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strength of tornado f0-f5
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The Enhanced Fujita Scale for classifying tornado strength is based on:
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multiple damage indicators and degree of damage.
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Damage to structures inflicted by tornadoes can be caused by:
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ALL OF THESE.
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After a tornado is spotted,
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a tornado warning is issued.
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A hook-shaped echo on a radar screen often indicates:
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possible presence of a tornado producing thunderstorm.
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The instrument that measures the speed at which precipitation is moving toward or away from an observer is:
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Doppler radar.
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The signal detected by a Doppler radar is:
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Radio wave reflected by precipitation.
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A single Doppler radar is NOT able to:
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measure speed at which rain is moving parallel to the radar antenna.
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A Doppler radar determines precipitation ____ by measuring changes in the____ of the reflected radiowave.
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velocity; frequency
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On a Doppler radar screen, a tornado vortex signature (TVS) appears as:
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region of rapidly changing wind speeds.
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Most waterspouts:
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have rotating winds and <45 knots.
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Which is NOT a characteristic of a "fair weather" waterspout?
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Stable atmosphere conditions.
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A tornado-like event that forms over water is a:
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Waterspout.
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Most waterspouts would fall into which category of the Enhanced Fujita Scale?
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F 0
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Light flashes darting upward from the tops of thunderstorms are called:
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Sprites and blue jets.
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Ordinary thunderstorms typically develop in warm, humid air masses ____ significant weather fronts.
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away from
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Supercell thunderstorms are much larger than ordinary thunderstorms and have ____.
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one large cell.
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Supercell thunderstorms ____ become severe.
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can
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According to the National Weather Service definition, a severe thunderstorm is a storm having:
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ALL OF THE ABOVE.
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The appearance of a downdraft marks the ____ of the mature stage of a thunderstorm.
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Beginning
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In a multicell storm, each of the cells is always in the same stage of development.
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FALSE (all different)
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A supercell storm consists of a single rotating updraft.
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TRUE
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Jet streaks are thought to have little to do with the development of severe thunderstorms.
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FALSE
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Conditional instability is a favorable condition for thunderstorm formation.
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TRUE (storms are generally unstable..)
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The atmospheric conditions that promote the formation of severe thunderstorms tend to prevent many smaller ones from forming.
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TRUE
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The cells that compose a multicell thunderstorm can be:
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In a different stage of development.
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The largest and most severe type of squall line forms:
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Ahead of cold fronts.
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The low-level jet stream reaches its maximum strength:
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Late at night/early morning.
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Severe thunderstorms often occur where the dryline intersects a front or an outflow boundary.
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TRUE
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The warm temperatures of a heat burst (a very warm thunderstorm downdraft) are caused by:
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compression