Deck 12: Middle-Latitude Cyclones

Question 1

Vorticity can be observed by satellites, even during cloudy conditions.

Answer 1

True

Question 2

Cyclogenesis can occur in regions without a large horizontal temperature gradient.

Answer 2

True

Question 3

Earth's vorticity can be positive or negative in the middle and high latitudes, depending on the hemisphere.

Answer 3

False

Question 4

Divergence aloft means that within this region, more air is entering than is leaving.

Question 5

Winds at the 500-mb level tend to steer surface systems in the same direction that the winds are moving.

Question 6

During baroclinic instability, the strong wind speed shear that exists from the surface up to a level of approximately 500 mb is disturbed by a shortwave.

Question 7

In the Southern Hemisphere, convergence and divergence play no roles in the development of middle latitude cyclones.

Question 8

In the polar front theory of a developing wave cyclone, energy for the storm is usually derived from an increase in surface winds, rising of warm air and sinking of cold air, and latent heat of condensation.

Question 9

A zone of organized clouds with precipitation can form in conjunction with a vorticity maximum, even in the absence of fronts.

Question 10

Mid-latitude cyclones usually "die out" after they become occluded because there is no longer a temperature contrast at the surface.

Question 11

During the development of a mid-latitude cyclone, the warm conveyer belt rises along the warm front.

Question 12

Like hurricanes, polar lows have a clear area in their center.

Question 13

Jet streaks often occur away from jet streams.

Question 14

The polar jet stream removes air above the surface anticyclone and supplies air to the surface cyclone.

Question 15

Aloft, waves are a fundamental feature of an unevenly heated, rotating sphere, such as Earth.

Question 16

The polar front theory of a developing wave cyclone was developed shortly after ____.

A)World War II
B)the Great Depression
C)World War I
D)the U.S. Civil War
E)the French Revolution

Question 17

The Colorado Low forms (or redevelops)on the eastern side of the Canadian Rockies in Alberta, then rapidly skirts across the northern tier of US states.

Question 18

Storms typically form along the polar front. However, there are also storms that develop over polar water behind (or poleward of)the main polar front.

Question 19

Like hurricanes, polar lows normally have a warmer central core, strong winds (often gale force or higher), and heavy showery precipitation that unlike a hurricane, is in the form of snow.

Question 20

Temperature advection does not occur when the winds do not cross the isotherms.

Question 21

When a deep upper-level trough is located to the east of a surface anticyclone, the surface anticyclone will tend to move toward the ____.

A)northwest
B)northeast
C)southwest
D)southeast
E)west

Question 22

The name ____ is given to a large cyclonic storm system that forms in the middle latitudes.

A)middle latitude cyclone
B)tornado
C)taifoon
D)anticyclone
E)thunderstorm

Question 23

In a mid-latitude cyclone, an upper-level pool of cold air that has broken away from the main flow is called a ____.

A)cut-off low
B)shortwave
C)wave cyclone
D)lee-side low
E)jet streak

Question 24

A surface low pressure area with a deep upper-level trough to the west will tend to move toward the ____.

A)northwest
B)northeast
C)southwest
D)southeast
E)south

Question 25

During the March, 1993 storm off the coast of Texas, a region of ____ air in the upper air above the storm caused the rapid decrease of surface pressure, leading to the development of a wave cyclone.

A)diverging
B)converging
C)blowing straight from west to east
D)increasing in speed uniformly over a broad area
E)blowing from north to south

Question 26

Which of the following regions of North America do not show a propensity for cyclogenesis?

A)The western slopes of the southern Cascades
B)The Gulf of Mexico
C)The Atlantic Ocean east of the Carolinas
D)The eastern slopes of the Rockies
E)The eastern slopes of the Sierra Nevada

Question 27

Which of the following is associated with rising air motions in a mid-latitude cyclone?

A)Shortwaves
B)Convergence of air at the surface
C)Convergence of air aloft
D)Divergence of air at the surface
E)Rossby waves

Question 28

For a surface storm system to intensify, the upper-level low (or trough)should be located to the ____ of the surface low.

A)north only
B)south only
C)east
D)west
E)either north or south

Question 29

The piling up of air above a region is called ____.

A)thickening
B)divergence
C)cyclogenesis
D)convergence
E)zonal front

Question 30

The development or strengthening of a middle latitude storm system is called ____.

A)convergence
B)divergence
C)cyclogenesis
D)frontolysis
E)frontogensis

Question 31

On a surface weather map that shows an open wave cyclone, the warm sector can be observed ____.

A)between the cold and warm fronts
B)behind an advancing cold front
C)ahead of an advancing cold-occluded front
D)behind an advancing cold-occluded front
E)ahead of an advancing warm front

Question 32

A lee-side low forms ____.

A)over the central Pacific Ocean
B)near the equator
C)on the upwind side of a mountain
D)on the downwind side of a mountain
E)over the Atlantic Ocean

Question 33

When an upper-level low lies directly above a surface low, ____.

A)the surface low will probably weaken
B)thunderstorms will develop
C)a wave cyclone will begin to form
D)the pressure of the surface low will decrease
E)cyclogenesis will occur

Question 34

Which of the following is one of the typical paths of a winter anticyclone in the United States?

A)Through northern Arizona, northern New Mexico, and eastern Colorado
B)Through Illinois, Wisconsin, and northern Michigan
C)Through eastern Ohio, western Pennsylvania, and western New York
D)Through western Washington, western Oregon, and western California
E)Through western Montana, western Wyoming, and western Colorado

Question 35

Northeasters (or nor'easters)are mid-latitude storms commonly found along ____.

A)the Pacific coast of North America
B)the Atlantic coast of North America
C)the Gulf coast of North America
D)both the Pacific and Atlantic coasts of North America
E)the Pacific coast of both North and South America

Question 36

According to the model of the life cycle of a wave cyclone, the storm system is normally most intense ____.

A)as a frontal wave
B)as a stable wave
C)as an open wave
D)as a stationary wave
E)when the system first becomes occluded

Question 37

If the flow of air into a surface low pressure area is greater than the divergence of air aloft, the surface pressure in the center of the low will ____.

A)increase
B)decrease
C)remain the same
D)deepen
E)drop rapidly

Question 38

As westerly winds blow over a north-south oriented mountain range, the airflow is deflected in such a way that a trough forms on the ____ side of the mountain.

A)upwind
B)downwind
C)both upwind and downwind
D)north
E)side

Question 39

The scientist ____ helped develop the polar front theory of a developing wave cyclone.

A)V. Bjerknes
B)C. G. Rossby
C)G. W. Whitmore
D)B. Franklin
E)T. Burger

Question 40

The ____ is considered to be a region where cyclogenesis often occurs.

A)eastern slopes of the Rocky Mountains
B)western slopes of the Rocky Mountains
C)California
D)Portland
E)Europe

Question 41

An upper-level trough that shows retrograde motion would be moving toward the ____.

A)west
B)east
C)north
D)south
E)northeast

Question 42

The ____ type of clouds indicate that a storm is still developing and intensifying.

A)cumulus
B)stratus
C)period
D)semicolon
E)comma

Question 43

Rossby waves are also known as ____.

A)stable waves
B)shortwaves
C)tidal waves
D)longwaves
E)macrowaves

Question 44

On an upper-level chart where the isotherms cross the isobars (or contours)and temperature advection occurs, the atmosphere is called ____.

A)barotropic
B)geostrophic
C)hydrostatic
D)baroclinic
E)barometric

Question 45

Atmospheric shortwaves usually move ____ at a speed that is ____ than longwaves.

A)east to west; faster
B)west to east; faster
C)north to south; slower
D)west to east; slower
E)south to north; slower

Question 46

A ____ disturbance imbedded in a longwave is called a shortwave.

A)small, stationary
B)large, stationary
C)small, moving
D)large, moving
E)None of these are correct.

Question 47

Sometimes, an upper-level pool of cold air that has broken away from the main flow lies almost directly above the surface low. Occasionally the upper low will break away entirely from the main flow, producing a ____.

A)jet streak
B)shear low
C)cut-off low
D)bent-back occlusion
E)polar jet stream

Question 48

Since the Northern Hemisphere's polar jet stream is strongest and moves farther south in ____, we can see why mid-latitude cyclonic storms are better developed and move more quickly during the ____ months.

A)spring; wetter
B)summer; warmer
C)fall; windier
D)winter; colder
E)spring and fall; wet and windy

Question 49

Vorticity refers to the ____.

A)rising and sinking of air along weather fronts
B)formation of clouds
C)spin of air parcels
D)changing of the seasons
E)development of a wave cyclone

Question 50

Divergence and convergence of air are due to changes in ____.

A)cloud pattern
B)solar radiation
C)radiational cooling
D)precipitation type
E)wind speed or wind direction

Question 51

Strong storms that develop over water, poleward of the polar front, are called ____.

A)nor'easters
B)upslope lows
C)lee-side lows
D)polar lows
E)tropical lows

Question 52

The entrance region occurs ____ of a jet streak, while the exit region occurs ____ of the jet streak.

A)downwind; upwind
B)upwind; downwind
C)ahead; above
D)downwind; above
E)above; below

Question 53

Lee-side lows are ____.

A)storms (extratropical cyclones)that form on the eastern (lee)side of a mountain range
B)thermal lows that form due to surface heating over deserts
C)storms (tropical cyclones)that form near the Leeward Islands
D)low pressure areas that form over oceans, then move onshore of the lee side of the coastline
E)storms that form on the lee side of lakes

Question 54

The planetary vorticity of an air parcel moving from low toward high latitude in the Northern Hemisphere will ____.

A)increase
B)decrease
C)remain constant
D)change from positive to negative
E)change from negative to positive

Question 55

The development of a mid-latitude cyclone, according to the Norwegian model, begins along the ____.

A)conveyor belt
B)wave cyclone
C)cyclone
D)incipient cyclone
E)anticyclone

Question 56

Atmospheric shortwaves usually move ____ longwaves, and ____ when they move through a longwave ridge.

A)faster than; weaken
B)faster than; strengthen
C)slower than; weaken
D)slower than; strengthen
E)at the same speed as; weaken

Question 57

In a mid-latitude cyclone, the warm sector is located ____.

A)behind the warm front
B)between the cold and warm fronts
C)below the occluded front and above the cold front
D)ahead of a stationary front
E)above the occluded front and below the cold front

Question 58

Which statement about vorticity is least accurate?

A)Earth's vorticity in the Northern Hemisphere is positive.
B)Earth's vorticity is zero at the poles.
C)Air that spins cyclonically possesses positive vorticity.
D)Absolute vorticity is the sum of Earth's vorticity and the relative vorticity.
E)Vorticity is the measure of the spin of small air parcels.

Question 59

If we assume that the absolute vorticity of flowing air is conserved, air moving northeastward will bend ____ to compensate for the ____ in Earth's vorticity.

A)anticyclonically; decrease
B)anticyclonically; increase
C)cyclonically; increase
D)cyclonically; decrease
E)cyclonically; lack of change

Question 60

Longwaves often ____, or even move ____.

A)remain stationary; retrograde
B)move quickly; retrograde
C)remain stationary; south
D)move quickly; south
E)move quickly; north

Question 61

Polar lows form most often during the ____.

A)spring
B)summer
C)fall
D)winter
E)spring or fall

Question 62

In late October 2012, ____________________ was one of the most dramatic combinations of tropical and extratropical cyclone processes ever observed.

Question 63

Divergence (or convergence)is a difficult task to measure with any degree of accuracy using upper-level wind information. Therefore, meteorologists must look for ____, something that can be measured and, at the same time, can be related to regions of diverging (and converging)air.

A)curvature
B)baroclinicity
C)cold advection
D)warm advection
E)vorticity

Question 64

With diameters of ____ or less, polar lows are generally smaller in size than their mid-latitude cousins.

A)10,000 to 5000 km
B)1000 cm to 10 m
C)1000 to 500 km
D)1 to 5 km
E)5 to 1 km

Question 65

The ___________________ is a semicontinuous global boundary separating cold polar air from warm subtropical air.

Question 66

Generally, a polar low's development is enhanced if an upper trough lies to the west of the surface system and a ____ disturbs the flow aloft.

A)anticyclone
B)cyclone
C)longwave
D)shortwave
E)nor'easter

Question 67

Earth's vorticity is always positive because the Earth spins ___________________ about its vertical North Pole axis.

Question 68

Cloud patterns in visible and infrared satellite images can be very helpful in identifying vorticity maxima in regions where clouds are present. In cloud-free areas, a type of infrared image called a(n)____ image measures wavelengths of radiation emitted by water vapor. The swirling patterns of moisture clearly identify the position of vorticity centers.

A)infrared
B)gas
C)cloud
D)water vapor
E)Doppler

Question 69

In a mid-latitude cyclone, when upper-level divergence of air above a surface low pressure area is stronger than the convergence of surface air (more air is taken out at the top than is brought in at the bottom), the surface pressure will ____________________ and the storm itself will ____________________.

Question 70

Divergence aloft causes a(n)____________________ in the cyclonic (positive)vorticity of surface cyclones, which usually results in ____________________ and upward air motions.

Question 71

When the wavelength of an upper-level wave is on the order of many thousands of kilometers, the wave is called a(n)____________________.

Question 72

In polar front theory, the region of warm air between the cold and warm fronts is known as the warm sector. Here, the weather tends to be ___________________.

Question 73

On a 500-mb chart, shortwave troughs can be difficult to detect. However, one way to identify them is to find regions of ____, with which shortwaves align themselves.

A)maximum vorticity
B)wind shear
C)minimum vorticity
D)advection
E)absolute vorticity

Question 74

Another term for frontal wave is ____.

A)overrunning
B)wave cyclone
C)cyclone
D)incipient cyclone
E)anticyclone

Question 75

Storms that form over polar water behind (or poleward of)the main polar front are called ____.

A)polar highs
B)poleward lows
C)leeside storms
D)arctic storms
E)polar lows

Question 76

Developing low pressure areas in mid-latitude cyclones generally have ____________________ air near the surface and ____________________ air aloft.

Question 77

In the conveyor belt model, directly below a _ ____________________, a cold airstream, known as the cold conveyor belt, is located.

Question 78

During baroclinic instability, a ____________________ lows often appear as single contour lines on an upper-level chart.

Question 79

When viewed from above, air that spins cyclonically (counterclockwise)has ____________________ and air that spins anticyclonically (clockwise)has ____________________.

Question 80

Generally, polar lows rapidly ____ when they move over land.

A)strengthen
B)dissipate
C)change direction
D)shears
E)double in strength