Exam 4

Question 1

What is an air mass?

Answer 1

A large body of air whose properties of temperature and humidity are fairly similar.

Question 2

What are source regions?

Answer 2

Regions where air masses originate.

Question 3

What is continental tropical air mass?

Answer 3

Hot and dry.

Question 4

What is continental arctic air mass?

Answer 4

Very cold and dry.

Question 5

What is maritime tropical air mass?

Answer 5

Warm and moist.

Question 6

What is continental polar air mass?

Answer 6

Cold and dry.

Question 7

What is a front?

Answer 7

The boundary between different air masses.

Question 8

What is a cold front?

Answer 8

Cold air moving into warm air.

Question 9

How fast does a cold front move?

Answer 9

30 mph.

Question 10

What is the ratio of a cold front?

Answer 10

1:50 (steep).

Question 11

What kind of weather comes with a cold front?

Answer 11

Short-lived heavy precipitation.

Question 12

As a cold front moves through, what happens to temperature?

Answer 12

There are sharp temperature drops.

Question 13

What is a warm front?

Answer 13

Warm air moving into colder air.

Question 14

How fast does a warm front move?

Answer 14

12 mph.

Question 15

What is the ratio of a warm front?

Answer 15

1:300 (shallower).

Question 16

What kind of weather comes with a warm front?

Answer 16

Long-lived light precipitation (can be sleet or freezing rain).

Question 17

Where are the clouds during a warm front?

Answer 17

Ahead of the warm front.

Question 18

What is a stationary front?

Answer 18

A boundary between two air masses which doesn’t move, bringing notable temperature change and a shift in wind direction.

Question 19

What is an occluded front?

Answer 19

An active cold front which overtakes a warmer front.

Question 20

How many air masses are involved in an occluded front?

Answer 20

Three air masses.

Question 21

What kind of weather comes with an occluded front?

Answer 21

A variety of precipitation intensities and duration.

Question 22

What is a cold type occluded front?

Answer 22

When cold air overtakes cool air and forces warm air up.

Question 23

What is a warm type occluded front?

Answer 23

When cool air overtakes cold air and forces warm air up.

Question 24

Which direction do frontal symbols point?

Answer 24

The direction of the frontal movement.

Question 25

What is a cyclone?

Answer 25

An area of low pressure.

Question 26

What direction do cyclone winds blow in the northern hemisphere?

Answer 26

Counterclockwise.

Question 27

What direction do cyclone winds blow in the southern hemisphere?

Answer 27

Clockwise.

Question 28

T/F: fronts are part of mid-latitude cyclones.

Answer 28

True.

Question 29

list the stages of cyclone development

Answer 29

stationary front, frontal wave, open wave, mature stage, occlusion, dissipating

Question 30

What happens when upper air divergence is stronger than surface convergence?

Answer 30

Surface pressure drops and the low intensifies.

Question 31

For the surface low to develop into a major storm system, what must occur?

Answer 31

Upper level air must be diverging.

Question 32

For a surface cyclonic storm to intensify, what must be present?

Answer 32

An upper level counterpart such as a trough that lies west of the surface low.

Question 33

What is a persistence forecast?

Answer 33

Future weather will be the same as present weather.

Question 34

What is a trend forecast?

Answer 34

Surface weather systems tend to move in the same direction at the same speed.

Question 35

What is an analogue forecast?

Answer 35

The future will be like weather historically occurred when similar conditions were present.

Question 36

What is numerical weather method?

Answer 36

NWP - uses the power of computers to make a forecast.

Question 37

What are the three conditions needed for a thunderstorm to form?

Answer 37

Moisture, unstable air mass, lifting force (heat).

Question 38

What stage of thunderstorm development is the most intense?

Answer 38

Mature stage.

Question 39

what stage of thunderstorm development is - updrafts dominate throughout the cloud and grow from a cumulus to a cumulonimbus?

Answer 39

Cumulus

Question 40

what stage of thunderstorm development is dominated by downdrafts and evaporation?

Answer 40

Dissipating

Question 41

What is wind shear?

Answer 41

How the wind changes speed/direction with height.

Question 42

Can wind shear tilt a storm's updraft?

Answer 42

True - this prolongs the storm.

Question 43

T/F: wind shear cannot enhance the rotation within the thunderstorm updraft.

Answer 43

False - it can, leading to the development of tornadoes.

Question 44

What classifies a severe thunderstorm?

Answer 44

Wind > 58 mph, hail > 1 in, tornadoes are reported.

Question 45

What are multicell thunderstorms?

Answer 45

Composed of multiple cells, each being at a different stage in the life cycle of a thunderstorm.

Question 46

What is a squall line thunderstorm?

Answer 46

A line of thunderstorms often forming along or ahead of a cold front.

Question 47

What is a supercell thunderstorm?

Answer 47

An intense, long-lasting thunderstorm with a single violently rotating updraft.

Question 48

What is a downburst?

Answer 48

A downdraft that becomes localized and hits the ground, spreading horizontally in a radial burst of wind.

Question 49

What is a gust front?

Answer 49

When cold downdraft reaches Earth's surface, it pushes outward in all directions.

Question 50

What is a tornado?

Answer 50

A rapidly rotating column of air that blows around a small area of intense low pressure.

Question 51

Which way does a tornado rotate?

Answer 51

Counterclockwise.

Question 52

What is the diameter of a tornado?

Answer 52

300-600 m.

Question 53

How fast does a tornado travel?

Answer 53

20-70 knots.

Question 54

How long does a tornado typically last?

Answer 54

A few minutes.

Question 55

What is the average path length of a tornado?

Answer 55

7 km.

Question 56

What is a mesocyclone?

Answer 56

Spinning horizontal vortex tubes created by surface wind shear may be tilted and forced in a vertical path by updrafts.

Question 57

What type of cyclone typically brings tornadoes?

Answer 57

Mesocyclone.

Question 58

Are hurricanes tropical cyclones?

Answer 58

True.

Question 59

How fast do winds have to be to be considered a hurricane?

Answer 59

>= 120 km/hr.

Question 60

What is the name of a hurricane in the West Pacific?

Answer 60

Typhoons.

Question 61

What is the name of a hurricane in the Atlantic and East Pacific?

Answer 61

Hurricanes.

Question 62

What is the name of a hurricane in the Indian Ocean and Australia?

Answer 62

Cyclones.

Question 63

How big is a typical hurricane?

Answer 63

600 km (1/3 size of mid-latitude cyclones).

Question 64

How long does a hurricane last?

Answer 64

Several days.

Question 65

T/F: Hurricanes have a large pressure difference so there's weak winds and fronts

Answer 65

False - they have strong winds and no fronts.

Question 66

What is the eye of a hurricane?

Answer 66

Typically relatively calm with light winds, generally clear, 20-40 miles across.

Question 67

What is the eyewall of a hurricane?

Answer 67

Typically adjacent to the eye, has the strongest winds and rain.

Question 68

What are rain bands?

Answer 68

Curved bands of clouds and thunderstorms that trail away from the eye wall in a spiral fashion.

Question 69

What do rain bands have?

Answer 69

Heavy bursts of rain and wind as well as tornadoes, sometimes gaps in between where no rain or wind is found.

Question 70

Where would you experience the highest pressure in a hurricane?

Answer 70

At the outer edge.

Question 71

Where would you experience the strongest pressure gradient in a hurricane?

Answer 71

In the eyewall.

Question 72

How warm does the ocean need to be for a hurricane to form?

Answer 72

Greater than 26.5° C.

Question 73

What conditions are needed for a hurricane to form?

Answer 73

Warm sea temps, unstable atmosphere, moist middle troposphere, coriolis force, weak vertical wind shear (in the opposite direction of the storm's motion).

Question 74

What are the four ways a hurricane can die?

Answer 74

Moving over cooler water, making landfall, encountering dry air, interacting with other weather systems.

Question 75

What kind of damage can hurricanes cause?

Answer 75

High winds damage structures and trees, tornadoes, heavy rain causes severe flooding and landslides, storm surge.

Question 76

For every 1 mb drop in atmospheric pressure, how much does sea level raise?

Answer 76

1 cm.

Question 77

What is wind-driven storm surge?

Answer 77

Hurricane winds pile up water near the coast.