Weather

Question 1

What causes weather?

Answer 1

The uneven heating of the earths surface which then heats the air around it

Question 2

In what layer of the atmosphere does weather occur?

Answer 2

Troposphere

Question 3

What is the standard lapse rate?

Answer 3

For every 1000’ increase the temperature decreases by 2 degrees C

Question 4

What happens as altitude increases?

Answer 4

Air pressure decreases

Question 5

What is the standard pressure at sea level?

Answer 5

29.92 Hg

Question 6

For every 1000’ of altitude gained, what happens?

Answer 6

The air pressure decreases by about 1” Hg

Question 7

What happens when the air is heated?

Answer 7

The air molecules spread apart and the air becomes less dense.

Question 8

When warm air rises, what happens?

Answer 8

Cooler air replaces it. The warm air cools as it rises creating condensation.

Question 9

For every 20 degree increase in temperature, what happens?

Answer 9

The amount of water vapor the air can hold is doubled.

Question 10

How does air move?

Answer 10

Always from an area of high pressure to an area of low pressure

Question 11

What does “H” mean?

Answer 11

Cool dry air = more stable = good weather

Question 12

What does “L” mean?

Answer 12

Warm rising air = more moisture/less stable = bad weather

Question 13

What is a front?

Answer 13

A boundary of changing air

Question 14

A warm air mass has what kind of front?

Answer 14

Warm Front - Represented by red bubbles

Question 15

A cold air mass has what kind of front?

Answer 15

Cold Front - Represented by blue Icicles

Question 16

Do warm fronts move faster or slower?

Answer 16

Slower - 10 - 15kts

Question 17

Do cold fronts move faster or slower?

Answer 17

Faster - 15 - 20kts

Question 18

What is relative humidity?

Answer 18

The ratio of how much water vapor the air can hold

Question 19

What is Dewpoint?

Answer 19

A specific temperature to determine relative humidity.
The air is 100% saturated

Question 20

As altitude increases what happens with temp. and dew point?

Answer 20

Temp. and Dewpoint get closer together.
When Temp = Dewpoint it causes: clouds, rain, and fog.

Question 21

What is stability in the atmosphere?

Answer 21

The atmospheres ability to resist vertical motion

Question 22

What are the biggest contributors to atmospheric stability?

Answer 22

Temperature and Moisture

Question 23

Hot, moist, fast moving air means what?

Answer 23

violent weather

Question 24

How does moisture get added to the air?

Answer 24

Evaporation and Sublimation

Question 25

What is sublimation?

Answer 25

A solid turns into a vapor. Requires an air pressure decrease and an increase in temperature.

Question 26

What is Fog?

Answer 26

A cloud on the ground.

Question 27

How many types of fog are there?

Answer 27

Advection - Precipitation - Radiation - Ice - Upslope - Steam -

Question 28

How does advection fog form?

Answer 28

Warm moist air moves over a cool surface. Such as in coastal areas

Question 29

How does precipitation fog form?

Answer 29

When warm rain or drizzle falls through a layer of cooler surface level air

Question 30

How does radiation fog form?

Answer 30

Forms on calm, clear nights, when the ground radiated its heat away.

Question 31

How does ice fog form?

Answer 31

When moisture in the air freezes and created tiny ice particles.

Question 32

how does upslope fog form?

Answer 32

Air moves up a surface and cools to its dew point

Question 33

How is steam fog form?

Answer 33

Cold dry air moves over warm water

Question 34

What are the 4 groups of clouds?

Answer 34

High, Middle, Low, and Clouds with vertical development.

Question 35

High clouds

Answer 35

20,000' AGL Cumulonimbus = forms in unstable air Cirrostratus, Cirrocumulus, Cirrus

Question 36

Middle clouds

Answer 36

6,500' - 20,000' AGL Altostratus = Turbulence & Icing Altocumulus = Light Turbulence & Icing

Question 37

Low clouds

Answer 37

SFC - 6,500' AGL Stratus, Stratocumulus, Nimbostratus.

Question 38

"nimbo" when referring to clouds means?

Answer 38

rain

Question 39

Clouds with vertical development

Answer 39

Low - High Warm, moist, unstable air Rises quickly

Question 40

Acceptable weather sources

Answer 40

Foreflight, Aviationweather.gov, NOAA, FSS, 1800WXBRIEF

Question 41

What is the order of a weather brief?

Answer 41

ADVERSE CONDITIONS VFR FLIGHT SYNOPSIS ENROUTE CONDITIONS CURRENT CONDITIONS WINDS AND TEMPS ALOFT NOTAMS DELAYS OTHERS (PIREPS. ETC.)

Question 42

How often are METARS updated? What range do they cover?

Answer 42

every 55 minutes past the hour 5sm

Question 43

What is a SPECI

Answer 43

A SPECI is a special METAR given when weather changes quickly.

Question 44

What two cloud conditions have ceilings?

Answer 44

Only broken and overcast

Question 45

What is a TAF? How often are they issued? What range do they cover?

Answer 45

Terminal Aerodrome Forecast Every 6 hours and are valid for 24-30 hours (30 is for international airports). 5sm.

Question 46

What is an Occluded front?

Answer 46

a fast moving cold front overtaking a slow moving warm front, lifting it off the ground.

Question 47

What is a stationary front?

Answer 47

Neither the cold nor the warm front is able to overtake the other.