Deck 12: Middle-Latitude Cyclones

Question 1

Which of the following is an accurate statement about polar lows?

A)They are smaller than middle-latitude cyclones and typically form in winter.
B)They are smaller than middle-latitude cyclones and typically form in summer.
C)They are larger than middle-latitude cyclones and typically form in winter.
D)They are larger than middle-latitude cyclones and typically form in summer.

Answer 1

A

Question 2

Which of the following scientists was one of the meteorologists who helped develop the polar-front theory of a developing wave cyclone?

A)Rossby
B)Bjerknes
C)Thornthwaite
D)McSorley

Answer 2

B

Question 3

Nor'easters are middle-latitude storms. In which of the following regions are they commonly found?

A)along the Pacific coast of North America
B)along the Atlantic coast of Europe
C)along the Atlantic coast of North America
D)along the Gulf coast of North America

Answer 3

C

Question 4

In which of the following orders of measurement are the lengths of longwaves in the middle and upper troposphere usually described?

A)tens of km
B)hundreds of km
C)thousands of km
D)millions of km

Question 5

Which of the following is another name given to a middle-latitude cyclone?

A)extratropical cyclone
B)frontal cyclone
C)anticyclone
D)deep cyclone

Question 6

Which of the following statements describes the usual speed and strength of atmospheric shortwaves?

A)They are slower than longwaves and weaken when they move through a longwave ridge.
B)They are faster than longwaves and weaken when they move through a longwave ridge.
C)They are faster than longwaves and strengthen when they move through a longwave ridge.
D)They are slower than longwaves and strengthen when they move through a longwave ridge.

Question 7

Which of the following is another name for Rossby waves?

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

Question 8

Which of the following describes the warm conveyor belt?

A)It is very dry.
B)It has few clouds associated with it.
C)It contains stratospheric ozone.
D)It rises above the warm front.

Question 9

Which of the following processes occurs when an anticyclone develops?

A)The anticyclone is causing a middle-latitude storm to form.
B)Separate anticyclones are merging.
C)The anticyclone is moving toward the east coast.
D)The central pressure is increasing.

Question 10

Which of the following is a characteristic that polar lows share with hurricanes?

A)temperature uniformly warm
B)weak Coriolis force
C)clear area in their centres
D)cloudy areas in their centres

Question 11

Which of the following defines the term vorticity?

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

Question 12

Which of the following describes the location where a lee-side low forms?

A)near the poles
B)near the equator
C)on the downwind side of a mountain
D)on the upwind side of a mountain

Question 13

Which of the following terms refers to a small, moving disturbance embedded in a longwave?

A)wave cyclone
B)lee-side low
C)frontal wave
D)shortwave

Question 14

Which of the following defines a comma cloud?

A)a high wispy cirrus cloud that takes on the shape of a comma
B)an organized band of clouds that looks like a comma on a satellite photograph
C)the spiraling arms of a hurricane
D)a large cumulonimbus cloud whose anvil is in the shape of a comma

Question 15

When a deep upper-level trough is located to the east of a surface anticyclone, in which of the following directions will the surface anticyclone tend to move?

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

Question 16

Which of the following terms refers to a strong storm that develops over water, poleward of the polar front?

A)nor'easter
B)upslope low
C)lee-side low
D)polar low

Question 17

Which of the following terms is true about middle-latitude cyclones in North America?

A)They travel from east to west.
B)They are less intense in the winter months.
C)They travel from south to north.
D)Their storm tracks shift to the south in winter, and to the north in summer.

Question 18

Hurricane Hazel is an example of a storm that had undergone which of the following?

A)tropical conversion
B)extratropical transition
C)teleconnection
D)middle-latitude transformation

Question 19

For cyclogenesis to occur along a frontal wave, which of the following conditions must be exhibited by the winds directly aloft of the wave?

A)convergence
B)direct movement from west to east
C)divergence
D)uniform increase in speed over a broad area

Question 20

Which of the following statements describes the usual direction and speed of atmospheric shortwaves?

A)They move west to east, and are faster than longwaves.
B)They move east to west, and are slower than longwaves.
C)They move east to west and are faster than longwaves.
D)They move west to east, and are slower than longwaves.

Question 21

In winter, most middle-latitude cyclones that impact southern Ontario come from which direction?

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

Question 22

Which of the following is the likely direction of movement of an upper-level trough that shows retrograde motion?

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

Question 23

According to the polar front theory of a developing wave cyclone, the energy for a storm is usually derived from several sources. Which of the following is one of the sources of energy for a storm?

A)latent heat of condensation
B)sinking of warm air
C)heat energy stored in the ground
D)a decrease in surface winds

Question 24

Assume that the absolute vorticity of flowing air is conserved. If air is moving northeastward, which of the following statements is correct?

A)Air will bend anticyclonically to compensate for an increase in the Earth's vorticity.
B)Air will bend cyclonically to compensate for a decrease in the Earth's vorticity.
C)Air will bend anticyclonically to compensate for a decrease in the Earth's vorticity.
D)Air will bend cyclonically to compensate for an increase in the Earth's vorticity.

Question 25

Which of the following processes occurs during baroclinic instability?

A)reduction of wave cyclones
B)no air motion
C)weak wind speed shear from the surface up to at least the 500 hPa level
D)temperature advection

Question 26

Why does occlusion occur in a middle-latitude cyclone?

A)Warm fronts travel more quickly than cold fronts.
B)Warm fronts and cold fronts travel at the same speed.
C)Cold fronts travel more quickly than warm fronts.
D)Cold air rises up and over warm air.

Question 27

Which of the following is the name given to the piling up of air above a region?

A)divergence
B)thickening
C)convergence
D)cyclogenesis

Question 28

Which of the following defines lee-side lows?

A)extratropical cyclones that form on the eastern or downwind side of a mountain range
B)thermal lows that form due to surface heating over deserts
C)low-pressure areas that form over oceans and then move onto a coastline's lee side
D)tropical cyclones that form near the Leeward Islands

Question 29

Which of the following locations is considered a region where cyclogenesis often occurs?

A)Atlantic Ocean near Halifax, Nova Scotia
B)eastern slopes of the Appalachian mountains
C)California
D)Gulf of Mexico

Question 30

According to the model of a wave cyclone life cycle, in which of the following situations does a storm system usually become most intense?

A)when it becomes a frontal wave
B)when it becomes an open wave
C)when it becomes a stable wave
D)when it first becomes occluded

Question 31

Which of the following terms is used when a middle-latitude storm system develops or strengthens?

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

Question 32

Chart
​
Refer to the diagram above.
In which of the following directions would a person located at the Earth's surface beneath position 2 observe clouds moving overhead (at the 500 hPa level)?

A)northwest to southeast
B)southwest to northeast
C)southeast to northwest
D)west to east

Question 33

Chart
​
Refer to the diagram above.
Where would a surface high-pressure area moving toward the southeast most likely be found?

A)1
B)2
C)3
D)4

Question 34

Which of the following conditions will occur when an upper-level low lies directly above a surface low?

A)Thunderstorms will develop.
B)A wave cyclone will begin to form.
C)The surface low will probably weaken.
D)The pressure of the surface low will decrease.

Question 35

At which number would a developing wave cyclone most likely be found?

A)1
B)2
C)3
D)4

Question 36

Which conveyor belt is responsible for the comma head of a middle-latitude cyclone?

A)cold conveyor belt
B)dry conveyor belt
C)warm conveyor belt
D)stratospheric conveyor belt

Question 37

Which of the following is an accurate statement about the dry conveyor belt?

A)It is associated with the clouds within a middle-latitude cyclone.
B)It is the cause of a middle-latitudes precipitation.
C)It brings calm conditions to the surface.
D)It can bring down air from the lower stratosphere.

Question 38

Which of the following defines cyclogenesis?

A)the weakening or dissipation of a middle-latitude cyclone
B)the development or strengthening of a middle-latitude cyclone
C)the exact midpoint of a middle-latitude cyclone
D)the development or strengthening of a tropical cyclone

Question 39

Which of the following is an alternative term that meteorologists use for explosive cyclogenesis?

A)cut-off low cyclogenesis
B)lee-side low development
C)bomb
D)deepening shortwave

Question 40

Which of the following is true about the Pineapple Express?

A)It causes nor'easters to form.
B)It brings heavy rainfall to the West Coast.
C)It is part of the polar jet stream.
D)It is caused by El Niño.

Question 41

When a surface low-pressure area with a deep upper-level trough is to the west, in which of the following directions will it tend to move?

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

Question 42

Which of the following air conditions generally occur when low-pressure areas are developing?

A)diverging air near the surface and diverging air aloft
B)converging air near the surface and converging air aloft
C)converging air near the surface and diverging air aloft
D)diverging air near the surface and converging air aloft

Question 43

For a surface storm system to intensify, the upper-level low would be located in which direction relative to the surface low?

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

Question 44

Describe with a sketch, a wind flow pattern that results in upper-level divergence.

Question 45

With the aid of a diagram, show why an intensifying surface low-pressure centre, located just east of a deep upper-level trough, will often move in a northeasterly direction.

Question 46

Suppose the outflow of air around a surface high-pressure area is greater than the convergence of air aloft. Which of the following conditions would be observed?

A)decrease in the central pressure
B)increase in pressure in the centre of the high
C)movement of the high toward the northeast
D)strengthening in the high

Question 47

When making a weather forecast, which kind of chart is more important: a surface chart or a 500 hPa chart? Why?

Question 48

Consider an air parcel that moves from low to high latitude in the northern hemisphere. Which of the following describes what happens to the planetary vorticity?

A)It decreases.
B)It increases.
C)It remains constant.
D)It changes from positive to negative.

Question 49

Which of the following terms refers to the atmosphere as shown on an upper-level chart where isotherms cross the contours and temperature advection occurs?

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

Question 50

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

A)ahead of an advancing cold-occluded front
B)behind an advancing cold front
C)behind an advancing cold-occluded front
D)ahead of an advancing cold front

Question 51

Which of the following is accurate regarding the development and intensification of a middle-latitude cyclone?

A)The life cycle of a middle-latitude cyclone averages about one month.
B)Development is not related to the pressure gradient force.
C)A middle-latitude cyclone involves two fronts and three air masses.
D)Intensification cannot occur along the polar front.

Question 52

Describe some of the ways in which an upper-level wind flow pattern can influence the development and movement of a middle-latitude storm system.

Question 53

Which of the following is the name for an upper-level pool of cold air that has broken away from the main flow?

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

Question 54

On a 500 hPa chart, why does middle-latitude cyclone development occur beneath troughs rather than ridges?

Question 55

If a shortwave passes over your location, what kind of weather might be expected?

A)clear skies followed by scattered clouds
B)several days of sunny weather
C)a short time of precipitation followed by clearing skies
D)several days of unsettled weather

Question 56

Define the term cyclogenesis. List some of the regions in Canada where cyclogenesis is common.

Question 57

What does the term "shortwave" refer to? Why is it important to locate and follow the movements of atmospheric shortwaves? How is this done? How is a shortwave different from a "longwave?"

Question 58

Suppose you observe a middle-latitude cyclone on a surface weather map. What kinds of weather charts would you examine to determine whether the cyclone is likely to strengthen or decay over the next 24 hours? What information would you likely gain from each chart type?

Question 59

In which of the following countries did the polar front theory of a developing wave cyclone originate?

A)Great Britain
B)Germany
C)United States
D)Norway

Question 60

Which of the following is the first to occur in the life cycle of a middle-latitude cyclone?

A)fully developed warm front
B)cut-off cyclone
C)occluded cyclone
D)open wave

Question 61

Sketch a 500 hPa chart that clearly shows a trough and a ridge. Where do you expect to find the maximum and minimum values of absolute vorticity? Where do you expect to find converging and diverging wind motions? Below what point on your 500 hPa chart do you expect middle-latitude storm development to occur?

Question 62

What are diffluence and speed divergence? How do these differ from confluence and speed convergence?

Question 63

Describe or illustrate the various phases in the life cycle of a middle-latitude storm according to the polar front theory.