Fundamentals of Weather

Question 0

What is the standard temperature for sea level?

Answer 0

15°C / 32°F

Question 1

At what rate does atmospheric pressure decrease with an increase in altitude?

Answer 1

Decreases approximately 2” Hg per 1,000 ft

Question 2

What is the standard pressure value for sea level?

Answer 2

29.92”

Question 3

What is the general characteristics in regards to flow of air around high-pressure systems in northern hemisphere?

Answer 3

Air flows inward, upward, and counterclockwise

Question 4

What is the general characteristics in regards to flow of air around low-pressure systems in northern hemisphere?

Answer 4

Air flows outward, downward, and clockwise

Question 5

What causes the winds aloft to flow parallel to the isobars?

Answer 5

Coriolis force

Question 6

Why do you surface winds generally flow across the isobars at an angle?

Answer 6

Surface friction

Question 7

What happens when temperature and dew point close together?

Answer 7

Visible moisture is likely, inform of clouds, dew, or fog

Question 8

What factor primarily determines the type and vertical extent of clouds?

Answer 8

Stability of the atmosphere

Question 9

What is the difference between stable and unstable atmosphere?

Answer 9

Stable atmosphere resist any upward or downward displacement.

Unstable atmosphere allows upward or downward displacement to grow into a vertical or convective current.

Question 10

How do you determine the stability of the atmosphere?

Answer 10

When temperature decreases uniformly and rapidly as you climb, you have an indication of unstable air.

If temperature remains unchanged or decreases only slightly with altitude, air is stable.

Question 11

What are the main types of icing an aircraft may encounter?

Answer 11

Structural, induction system, and instrument icing

Question 12

What are the three types of structural icing?

Answer 12

Clear ice, Rime ice, mixed ice

Question 13

Define clear ice:

Answer 13

Large drops and slowly freezes

Question 14

Define Rime ice:

Answer 14

Small drops and freezes rapidly

Question 15

Define mix ice:

Answer 15

Combination of clear and Rime ice

Question 16

What is induction icing?

Answer 16

Carburetor engine ice.

Carb heat 10 to 15 minutes or until landing

Question 17

What is instrument icing?

Answer 17

Pitot icing, nav antenna iced

Question 18

What factors must be present for a thunderstorm to form?

Answer 18

A source of lift, heating, fast-moving front to lift/upslope.

Unstable air.

High moisture content.

Question 19

What are the stages of a thunderstorm?

Answer 19

Cumulus stage: updrafts

Mature stage: first sign of rainfall begins

Dissipating stage: rain themselves out

Question 20

What are squall line thunderstorms?

Answer 20

A non-frontal, narrow band of active thunderstorms.

Often develops ahead of cold front and moist, unstable air, but it may develop an unstable air far removed from any front.

Question 21

How far do you circumnavigate a thunderstorm?

Answer 21

20 nautical miles around

Question 22

How do you proceed if caught in a thunderstorm?

Answer 22

Wings level, maneuver speed

Question 23

State two basic ways that a fog may form:

Answer 23

Cooling air it the dew point.

Adding moisture to the air.

Question 24

Name the types of fog:

Answer 24

Ice fog Radiation fog Advection fog Precipitation induced fog Upslope fog

Question 25

What causes radiation fog to form?

Answer 25

Clear sky, little/no wind, small dew point spread. Forms during night/near daybreak.

Question 26

What is advection fog and where is it most likely to form?

Answer 26

Moist air over colder ground or water. Most common along costal areas. But often develops deep in continental areas.

Question 27

Define upslope fog:

Answer 27

Moist, stable air being cool adiabatically as it moves upsloping terrain. Once upsloping winds cease, fog dissipates. Rockies, Appalachian Mountains.

Question 28

Define Ice fog:

Answer 28

Occurs in cold whether when temperature is much below freezing and water vapor sublimates directly as ice crystals. Occurs mostly in Arctic regions.

Question 29

What is precipitation induced fog?

Answer 29

When relatively warm air/drizzle falls thru cool air, evaporation from precipitation saturates cool air and forms fog. Most commonly associated with warm fronts but also slow moving cold fronts and stationary fronts. Industrial pollution also can cause this

Question 30

Other than fog, what are several other examples of IFR weather producers?

Answer 30

``` Low clouds Haze Smoke Blowing obstructions to vision Precipitation Fog ```

Question 31

What is a microburst?

Answer 31

Small scale down drafts. Originate from low/mid layer convective clouds. Can prove deadly to all planes.

Question 32

What are the characteristics of a microburst?

Answer 32

Max life of 15min. Against Microburst may encounter increased head winds. In the middle of microburst may encounter strong down drafts. With microburst may encounter improved performance.

Question 33

Define freezing level:

Answer 33

Altitude where snow, frost & ice are likely to drop