Lesson 8.5

Question 1

What is an air mass?

Answer 1

A large body of air with generally uniform temperature and humidity.

Question 2

What is a source region?

Answer 2

The area from which an air mass originates.

Question 3

Name the four classifications of air mass temperature properties.

Answer 3

• Arctic (A)
• Polar (P)
• Tropical (T)

Question 4

What are the two classifications of air mass moisture properties?

Answer 4

• Continental (c)
• Maritime (m)

Question 5

How does an air mass modify as it moves?

Answer 5

It can acquire different attributes based on the surface it moves over.

Question 6

What happens when an arctic air mass moves over the ocean?

Answer 6

It can become a maritime polar (mP) air mass.

Question 7

What is a cold front?

Answer 7

A boundary where a mass of cold, dense air replaces a warmer air mass.

Question 8

What weather conditions are typical before a cold front passes?

Answer 8

Cirriform or towering cumulus clouds and rain showers.

Question 9

What occurs after the passage of a cold front?

Answer 9

Cumulonimbus clouds dissipate to cumulus clouds and good visibility returns.

Question 10

What defines a warm front?

Answer 10

A warm air mass advances and replaces a colder air mass.

Question 11

What weather is expected during the passage of a warm front?

Answer 11

Stratiform clouds and drizzle.

Question 12

What is a stationary front?

Answer 12

A boundary between two air masses that remains in place for days.

Question 13

What happens in an occluded front?

Answer 13

A cold front catches up to a warm front, merging them.

Question 14

What are the two types of occluded fronts?

Answer 14

• Cold front occlusion
• Warm front occlusion

Question 15

What is wake turbulence?

Answer 15

Disturbance caused by counter-rotating vortices trailing from aircraft wingtips.

Question 16

What is convective turbulence?

Answer 16

Turbulence from vertical motions due to convective currents.

Question 17

What causes mechanical turbulence?

Answer 17

Obstructions to wind flow, such as buildings or mountains.

Question 18

What is wind shear?

Answer 18

Turbulence generated between two wind currents of different directions or speeds.

Question 19

What is Clear Air Turbulence (CAT)?

Answer 19

Sudden severe turbulence occurring in cloudless regions, typically above 15,000 ft.

Question 20

List the intensities of turbulence.

Answer 20

• Light
• Moderate
• Severe
• Extreme

Question 21

What is structural icing?

Answer 21

Ice that sticks to the outside of an airplane from supercooled water droplets.

Question 22

Name the three types of structural icing.

Answer 22

• Rime
• Clear
• Mixed

Question 23

What is the difference between deicing and anti-icing?

Answer 23

Deicing removes built-up ice; anti-icing prevents ice from forming.

Question 24

What is a thunderstorm?

Answer 24

A local storm produced by a cumulonimbus cloud, always accompanied by lightning and thunder.

Question 25

What are the three ingredients necessary for thunderstorm formation?

Question 26

What are the three stages of a thunderstorm's life cycle?

Answer 26

* Towering cumulus * Mature * Dissipating

Question 27

What characterizes the mature stage of a thunderstorm?

Answer 27

Precipitation reaches the surface, creating strong downdrafts.

Question 28

What is a gust front?

Answer 28

The arc-shaped leading edge of downdraft air resembling a miniature cold front.

Question 29

What is a storm cell?

Answer 29

A mass of cool, gusty air ## Footnote Storm cells are characterized by strong downdrafts and can trigger the formation of new cells along a gust front.

Question 30

What is a gust front?

Answer 30

The arc-shaped leading edge of downdraft air ## Footnote Gust fronts resemble a miniature cold front and can initiate new storm cells.

Question 31

What is an overshooting top?

Answer 31

Cumulonimbus tops that penetrate into the lower stratosphere ## Footnote Overshooting tops are influenced by strong winds aloft, causing the cloud top to take on an anvil shape.

Question 32

When do weather hazards reach peak intensity in a thunderstorm?

Answer 32

Toward the end of the mature stage ## Footnote This is when the storm is most powerful and hazardous.

Question 33

What characterizes the dissipating stage of a thunderstorm?

Answer 33

A strong downdraft embedded within the area of precipitation ## Footnote The updraft is cut off, leading to a tapering off of precipitation.

Question 34

What happens to the relative humidity during the dissipating stage?

Answer 34

It drops as compression warms the subsiding air ## Footnote This process contributes to the gradual vaporization of the cloud.

Question 35

What is left after the convective cloud vaporizes in the dissipating stage?

Answer 35

A remnant anvil cloud ## Footnote This is the last visible part of the thunderstorm as it dissipates.

Question 36

What are the hazards associated with thunderstorms?

Answer 36

Hazards include: * Low ceiling and visibility * Lightning * Adverse winds * Downbursts * Turbulence * Icing * Hail * Rapid altimeter changes * Static electricity * Tornadoes * Engine water ingestion ## Footnote These hazards can vary in combination and intensity.

Question 37

What should you do if unable to navigate around thunderstorms?

Answer 37

Divert and wait out the thunderstorms on the ground ## Footnote This is a safety measure to avoid the hazards associated with thunderstorms.

Question 38

How far should you avoid a severe thunderstorm?

Answer 38

At least 20 miles ## Footnote This distance increases to 40 miles when flying between echoes of large cumulonimbus storms.

Question 39

What are the types of thunderstorms?

Answer 39

Types include: * Single Cell * Multi Cell * Squall Line * Super Cell * Embedded Thunderstorms ## Footnote Each type has distinct characteristics and hazards.

Question 40

What is one type of front?

Answer 40

[key learning term] ## Footnote Example types of fronts include cold fronts, warm fronts, and stationary fronts.

Question 41

What is one type of turbulence?

Answer 41

[key learning term] ## Footnote Examples include clear air turbulence, mechanical turbulence, and thermal turbulence.

Question 42

What are the three stages of a thunderstorm?

Answer 42

Stages include: * Cumulus * Mature * Dissipating ## Footnote Each stage has specific characteristics and weather phenomena.