A107 WEATHER THEORY AND REPORTS

Question 1

What is the Atmosphere
made up of?

Answer 1

~ 78% Nitrogen, 20% Oxygen and
2% other gases

Question 2

What does the atmosphere contain?

Answer 2

Swirls, eddies, currents, and waves –
like the ocean

Question 3

What are the 4 layers of the Atmosphere?

Answer 3

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

Question 4

What layer of the atmosphere contains the jetstream?

Answer 4

Tropopause

Altitude varies with location and wx

Question 5

Where is the tropopause located?

Answer 5

At the top of the troposphere is a boundary known as the tropopause, which traps moisture and the
associated weather in the troposphere.

Question 6

Where does the vast majority of weather, clouds, storms, and temp variances occur?

Answer 6

Troposphere

Question 7

What is the major factor in circulation?

Answer 7

uneven heating of the earth’s surface by the sun

Question 8

Earths rotation is referred to as the ______________?

Answer 8

Coriolis Effect

Question 9

Air Circulation Patterns follow what direction?

Answer 9

Right

Question 10

Air flows ________ around high-pressure areas, and
_____________ around low-pressure areas

Answer 10

Clockwise, Counter-clockwise,

Question 11

________ refers to air moving horizontally from high pressure to low pressure

Answer 11

Wind

Question 12

As warmer air rises and small vertical air movements tend to become larger, what does that generate?

Answer 12

Turbulence and convective wx

Question 13

What is the Standard Temperature Lapse Rate?

Answer 13

2 deg C every 1000’ altitude increase

Question 14

Stable atmosphere makes ___________ _____________ difficult

Answer 14

Vertical Movement

Question 15

What is a Temperature Inversion?

Answer 15

An atmospheric anomaly where air gets warmer as altitude increases to a certain point.

Can result in restricted visibility

Question 16

Define Air Masses

Answer 16

Large bodies of air that take on characteristics of the surrounding area

Question 17

An air mass passing over a __________ surface is warmed from below and
convective currents form causing the air to rise

Answer 17

Warmer

Question 18

An air mass passing over a _________ surface does not form convective
currents, but creates a stable air mass with poor visibility

Answer 18

Colder

Question 19

What is a warm front?

Answer 19

Warm, humid air moves to replace a body of cold air
* Light to moderate precipitation probable
* Blanket type clouds (Stratus) likely

Question 20

What are the characteristics of a Cold Front?

Answer 20

• Cold, dense, stable air rapidly advances to displace a body of warmer air
• Stays close to the ground, acts like a snow plow

Generally more severe wx than warm fronts

Question 21

Clouds are classified by?

Answer 21

• By shape
• According to the height of their bases (Low, Middle or High)
• According to their behavior or vertical development

Question 22

Low clouds are below what AGL?

Answer 22

6500’

Question 23

From _______ to _________ ft AGL is the middle layer of clouds?

Answer 23

6500’ to 20,000’

Question 24

High clouds are above what AGL?

Answer 24

20,000’

Question 25

Low Clouds are?

Answer 25

Fog * Surface to 6,500’ AGL * Made primarily of water droplets, but can include supercooled water droplets

Question 26

Middle Clouds are?

Answer 26

* 6,500’ AGL to 20,000’ AGL * Composed of water, ice crystals and supercooled water droplets

Question 27

High clouds are?

Answer 27

* Form above 20,000 AGL * Form in stable air * Composed of ice crystals

Question 28

What are clouds with extensive vertical development?

Answer 28

* Cumulus clouds that build vertically to towering cumulus or cumulonimbus clouds

Question 29

What are the Three Stages of a Thunderstorm?

Answer 29

Cumulus (mostly updrafts) Mature (both up and downdrafts) Dissipating (mainly downdrafts)

Question 30

What is the most violent stage of a Thunderstorm?

Answer 30

Mature Stage (precipitation begins to fall with both updrafts and downdrafts)

Question 31

What are some Thunderstorm hazards to aviation?

Answer 31

* Updrafts / Downdrafts * Large Hail-stones * Lightning * Tornadoes

Question 32

What is Wind Shear?

Answer 32

* A sudden, drastic change in wind speed and/or direction over a very small area * Headwind changing to a Tailwind causes loss of aircraft performance * Low-level is most hazardous due to proximity to ground * Typically occurs with: Passing frontal systems, Thunderstorms, Temperature inversions, and Surface obstructions

Question 33

What is a critical type of shear associated with convective precipitation from a T-storm?

Answer 33

Microburst

Question 34

What is the typical horizontal diameter of a Micoburst?

Answer 34

* Typically has a horizontal diameter of 1 – 2 miles

Question 35

What is the typical lifespan of a microburst?

Answer 35

15 minutes

Question 36

Microbursts produce downdrafts up to _________ feet per minute (FPM)

Answer 36

6000

Question 37

An Aviation Routine Weather Report, hourly weather observation by a person or automated equipment is referred to as?

Answer 37

METAR

Question 38

Information for routine METAR reports is observed between _________ after the hour until the top of the hour

Answer 38

45 Minutes

Question 39

METAR is reported between ________ after the hour until the top of the hour

Answer 39

50 Minutes

Question 40

________ means the report came from an automated source

Answer 40

AUTO

Question 41

_______ means the report is a corrected observation

Answer 41

COR

Question 42

__ refers to a CONUS airport

Answer 42

K

Question 43

METARs report the ___________ visibility, which may differ from the tower visibility or flight visibility.

Answer 43

Prevailing

Question 44

________ visibility will be reported in the remarks section if it differs from the prevailing visibility and is less than 3 miles.

Answer 44

Sector

Question 45

Direction the winds are blowing ______ in degrees from 0 to 360 degrees

Answer 45

from

Question 46

METAR winds are reported as ________ ___________

Answer 46

True North

Question 47

A ____ symbol denotes a light intensity level

Answer 47

-

Question 48

A ___ symbol denotes a heavy intensity level

Answer 48

+

Question 49

VC indicates a specific weather condition in the ______ of the airport

Answer 49

Vicinity (w/i 5 and 10 statute miles from the reporting station)

Question 50

In temperature the "M" refers to?

Answer 50

Minus, so M14 would me -14deg C

Question 51

‘A’ stands for _________

Answer 51

Altimeter

Question 52

Use altimeter data to calculate what?

Answer 52

Pressure Altitude for Performance Data

Question 53

A Terminal Aerodrome Forecast (TAF) is a?

Answer 53

Concise statement of the expected meteorological conditions for a 5 statute mile radius

Question 54

AMD is an

Answer 54

Amended forecast

Question 55

Routine TAFs are prepared and filed approximately ______________ prior to scheduled issuance times.

Answer 55

one-half hour

Question 56

TAFs are scheduled for issuance four times daily, what are they?

Answer 56

0000Z, 0600Z, 1200Z, & 1800Z

Question 57

Routine TAFs are valid for how long?

Answer 57

24 hours

Question 58

VRB would indicate?

Answer 58

Variable winds

Question 59

Forecast visibility greater than 6 statute miles is indicated by _______

Answer 59

P6SM

Question 60

BR is ______

Answer 60

mist

Question 61

Obscurations are identified when the prevailing visibility is forecasted to be _____ statute miles or less.

Answer 61

6 SM

Question 62

When clear skies are forecast what is used?

Answer 62

SKC

Question 63

Code for wind sheer?

Answer 63

WS

Question 64

For wind shear, Height is given in hundreds of feet AGL up to and including __________

Answer 64

2,000' AGL

Question 65

The ___________ group is used when a rapid change in conditions is expected, usually occurring in less than one hour.

Answer 65

FROM (FM)

Question 66

The ___________ group is used when a gradual change in conditions is expected over a longer time period, usually two or more hours

Answer 66

Becoming (BECMG) group (more gradual)

Question 67

The ______________ group is used for any conditions in wind, visibility, weather, or sky condition which are expected to last for generally less than an hour at a time.

Answer 67

Temporary (TEMPO)