Deck 12: Middle Latitude Cyclones

Question 1

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.​

Answer 1

True

Question 2

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

Answer 2

True

Question 3

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.​

Answer 3

True

Question 4

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

Question 5

In the Southern Hemisphere,convergence and divergence play a role in the development of middle latitude cyclones.​

Question 6

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

Question 7

The dry conveyor belt forms in the cold,very dry region of the upper mesosphere.​

Question 8

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

Question 9

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

Question 10

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

Question 11

Jet streaks often occur away from jet streams.​

Question 12

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

Question 13

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

Question 14

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 15

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 16

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

Question 17

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

Question 18

The polar front theory of a developing wave cyclone was conceived in​

A)Norway.
B)Great Britain.
C)​the United States.
D)​Germany.
E)​the Soviet Union.

Question 19

Vorticity is always present in the atmosphere,even during fair weather.​

Question 20

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

Question 21

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

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

Question 22

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 23

Cyclogenesis is the ____ of a mid-latitude cyclone.​

A)development or strengthening
B)weakening or dissipation
C)​term for the exact midpoint
D)​shifting
E)​re-direction

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

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 26

Which scientist helped develop the polar front theory of a developing wave cyclone?​

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

Question 27

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 28

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 29

The piling up of air above a region is called​

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

Question 30

Which region 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 31

Northeasters (or nor'easters)are midlatitude 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 32

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 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

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 35

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 36

Another term for explosive cyclogenesis used by meteorologists is​

A)volcano.
B)breakaway.
C)​burst.
D)​flare.
E)​bomb.

Question 37

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 38

Which 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 39

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 40

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 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 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 43

What type of clouds indicate that a storm is still developing and intensifying?​

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

Question 44

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 45

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 46

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 47

A small,moving disturbance imbedded in a longwave is called a​

A)lee-side low.
B)wave cyclone.
C)​shortwave.
D)​frontal wave.
E)​Rossby wave.

Question 48

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 49

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 50

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 51

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 52

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 53

Longwaves in the middle and upper troposphere usually have lengths on the order of​

A)a few kilometers.
B)tens of kilometers.
C)​hundreds of kilometers.
D)​thousands of kilometers.
E)​millions of kilometers.

Question 54

In a mid-latitude cyclone,when the upper low lies directly above the surface low,the storm system is said to be​

A)horizontally stacked.
B)vertically unstable.
C)​vertically stacked.
D)​horizontally unstable.
E)​vertically cut off.

Question 55

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 56

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 57

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 58

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 59

Rossby waves are also known as

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

Question 60

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 61

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 else that can be measured and,at the same time,can be related to regions of diverging (and converging)air.That something is called​

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

Question 62

The polar front is a semicontinuous global boundary separating cold ____________________ air from warm ____________________ air.

Question 63

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 64

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

Question 65

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 66

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

Question 67

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

Question 68

In polar front theory,the region of warm air between the cold and warm fronts is known as the ____________________.

Question 69

Cyclones that normally move northeastward along the Atlantic Coast,bringing high winds and heavy snow or rain to coastal areas,are referred to as ____________________.

Question 70

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 71

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 72

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

Question 73

Polar lows form most often during the

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

Question 74

____________________ is the transfer of vorticity (the rate of horizontal spin of air parcels)by wind.​

Question 75

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

A)north
B)east
C)​south
D)​west
E)​north or south

Question 76

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

Question 77

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

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

Question 78

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 79

Another term for Earth's vorticity is ____________________ vorticity.

Question 80

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