Block 4 Study Guide

Front 1

What is the lowest layer of the atmosphere that contains almost all clouds and precipitation?

Back 1

Troposphere

Front 2

What is an inversion?

Back 2

An increase in temperature with altitude (which is abnormal)

Front 3

What is the size of the troposphere?

Back 3

About 36,000 ft average, 65,000 ft at the equator, 20,000 ft at the poles

Front 4

What is the transition boundary between the troposphere and stratosphere called?

Back 4

Tropopause

Front 5

What is the standard atmosphere pressure, temperature, lapse rate and altitude?

Back 5

29.92 in of mercury,

15 deg Cel/59 deg F,

Decrease of temp with height 2 deg C, 3.5 deg F per 1,000 feet,

altitude 36,000 feet

Front 6

What is standard atmosphere used for?

Back 6

Pressure altimeter calibrations, performance calculations, design and weather related processes

Front 7

What is a jet stream?

Back 7

Relatively strong wind concentrated within a narrow horizontal band in the upper troposphere

Front 8

How many types of jet streams exist and how does a jet stream flow?

Back 8

There are 2, Polar (30 to 60) and Subtropical (20 to 40). Jet streams flow west to east

Front 9

When are jet streams strongest and what do they do to an aircrafts airspeed?

Back 9

Strongest during the winter, the cause aircraft to move at different ground speeds

Front 10

What does often produce CAT?

Back 10

Jet streams

Front 11

What is sublimation?

Back 11

The change of ice to water vapor

Front 12

What is the raw material for clouds and precipitation?

Back 12

Water vapor

Front 13

Where is water vapor found and how much does it constitute?

Back 13

Trace amounts to 4%, found below 6,500 AGL

Front 14

Warm air can hold............than cold air

Back 14

more water vapor

Front 15

What is saturation?

Back 15

The max quantity of water vapor that a parcel of air can hold at any temp or pressure

Front 16

What does unsaturated mean?

Back 16

A parcel of air can still hold more water vapor

Front 17

What is dew point?

Back 17

The temp at which a parcel of air must be cooled at constant pressure and water vapor for saturation to occur

Front 18

What do higher dew points at a location mean?

Back 18

There is a higher quantity of water vapor at the location

Front 19

What is relative humidity?

Back 19

The percentage of water vapor versus what air could hold at a particular temp and pressure point

Front 20

What is spread?

Back 20

The difference between air temperature and dew point

Front 21

What happens when the temperature dew-point spread decreases to zero?

Back 21

The air becomes saturated and condensation will form dew, fog or clouds

Front 22

What is condensation?

Back 22

The change of water vapor to liquid water

Front 23

What is the most common way for clouds to form?

Back 23

Via condensation of water vapor in rising air currents

Front 24

Whats the process behind cloud formation?

Back 24

A parcel of rising air cools as pressure decreases with altitude. Temp decreases and temp-dew-point spread decreases

Front 25

Whats the process behind cloud dissipation?

Back 25

A parcel of sinking air warms up as pressure increases. Temp increases and temp-dew-point spread increases

Front 26

What are the three basic types of clouds and their characteristics?

Back 26

Cirriform (High level, 20,000 ft, thin, ice crystals), Cumuliform (Fluffy cotton balls, can produce icing, turbulence) and Stratiform (low level, widespread IFR weather)

Front 27

What is a wind high meteorological effect?

Back 27

Anti-cyclone, air flow around a high diverges clockwise and sinks, warming the air and clouds dissipate

Front 28

What is a low wind meteorological effect?

Back 28

Cyclone, Air flow around a low converges counter-clockwise and rises. Cools the air, clouds form

Front 29

What are the five air mass source regions?

Back 29

Artic continental (cold and dry) Ca

Polar Continental (Cold, dry) cP

Polar Maritime (Cool, moist) mP

Tropical Continental (Hot, dry) cT

Tropical Maritime (Warm, moist) mT

Front 30

What happens when a cold air mass goes over a warm air surface?

Back 30

Unstable air is produced, cumuli form clouds and showers, turbulence, good visibility outside of clouds

Front 31

What happens when warm air goes over a cold air surface?

Back 31

Stable air is produced, poor visibility, low stratiform clouds, fog, drizzle, smooth air

Front 32

What is a front and how many are there?

Back 32

It's a transition zone between two air masses of different density. Cold front, warm front, stationary front, occluded front

Front 33

Cold fronts have........ and air is forced.........

Visibility is...... Clouds are.......

Back 33

Steep slope and air forced up abruptly, good visibility and turbulence, cumulus clouds

Front 34

Warm fronts have........ and air rises.....

Visibility is ....... Clouds are......

Back 34

Gentle slope and air rises gradually, poor visibility, clouds are stratiform and layered

Front 35

Precip requires three items....

Back 35

Water vapor, lift and growth process

Front 36

_____ occurs when there is a shallow layer above and deep layer below of freezing air

Back 36

Ice pellets

Front 37

_____ occurs when there is a deep warm layer above a shallow cold layer

Back 37

Freezing rain

Front 38

What products are released by the NWS?

Back 38

Airmets, Sigmets, Convective Sigmets, Tafs

Front 39

What does the CWSUs issue?

Back 39

CWA (Center weather advisories) and MIS (Meteorological Impact Statements)

Front 40

Controllers shall advise pilots of haz weather within.....

Back 40

150 NM of their sector or area of jurisdiction

Front 41

What is the cause of most weather related accidents?

Back 41

Adverse wind

Front 42

What can a gust cause to an aircraft during takeoff roll?

Back 42

An aircraft to bounce on the runway and possibly crash

Front 43

What is tailwind?

Back 43

Any wind that is more than 90 degrees to the longitudinal axis of the runway

Front 44

What occurs during a tailwind takeoff and landing?

Back 44

A longer takeoff roll is required, smaller rate of climb, longer landing roll

Front 45

What is considered variable wind?

Back 45

When during the 2 min eval period, the wind fluctuates by 60 degrees and +/- 6 knots

Front 46

What is a wind shift?

Back 46

When the wind changes direction by 45 degrees or more, less than 15 minutes, 10 knots or more

Front 47

IFR weather is the greatest cause of .....

Back 47

fatal accidents

Front 48

Indefinite ceiling

Back 48

Surface based obscuration

Front 49

Ceiling

Back 49

Lowest layer aloft

Front 50

Fog

Back 50

Droplets reducing horizontal vis less than 5/8 SM

Front 51

What is the most common and persistent weather hazard encountered in aviation?

Back 51

Fog

Front 52

Blowing snow.....

Back 52

6 feet or more, visibility less than 7 SM

Front 53

What precip types are mostly common with IFR weather?

Back 53

Snow, rain, drizzle

Front 54

What causes turbulence?

Back 54

Convective turbulence, mechanical turbulence, wind shear

Front 55

When do convective turbulence mostly occur?

Back 55

Warm summer afternoons, billowy cumuliform clouds

Front 56

What is directly related to mechanical turbulence?

Back 56

Wind speed, obstructions

Front 57

Where do Mountain waves develop?

Back 57

Above and downwind from mountains

Front 58

What is wind shear and the 3 conditions of wind shear?

Back 58

A change in wind speed/distance in a short period of time.

Low level temperature inversion

Frontal Zone

Clear Air turbulence (CAT)

Front 59

When does air temp inversion occur?

Back 59

Valleys, frontal zones, nighttime cooling

Front 60

When does CAT (Clear air turbulence) occur? When is it strongest?

Back 60

It occurs at higher altitudes (20K ft and above) in cloud free areas where jet streams affect the surrounding air

Strongest during the winter

Front 61

What are the types of turbulence?

Back 61

Light, Moderate, Severe, Extreme

Front 62

Which of the following clouds would provide visual proof that a mountain wave exists?

What kind of turbulence does it create?

Back 62

A rotor cloud

Severe to extreme turbulence

Front 63

When the air is too dry for cumuliform clouds to form_______ currents caused by uneven surface heating can still be be active and cause turbulence

Back 63

Convective

Front 64

What is structural icing?

Back 64

Icing that sticks to the outside of an airplane

Front 65

What are the three types of ice, how do they form?

Back 65

Rime (instantaneous), Clear (slow), Mixed (combines both)

Front 66

What are the four icing intensity levels?

Back 66

Trace (not unless over 1 hour), light (used over 1 hour), moderate (anti ice necessary), severe (anti ice fails)

Front 67

Droplets of supercooled water often exist in......

Back 67

Stratiform and cumulus clouds

Front 68

Icing occurs due to ....

Back 68

Aircraft type, altitude, airspeed, meteorological factors

Front 69

Commercial jets are less prone due to...

Back 69

Flying at higher altitudes -40 degrees celcius, turboprops fly at 0 to -20 degrees celcius

Front 70

Icing can reduce lift by how much on an aircraft?

Back 70

Lift by 30% and drag by 40%, larger accumulations by 80%

Front 71

What cloud and weather types are associated with thunderstorms?

Back 71

Cumulonimbus, IFR weather, adverse wind, icing, turbulence, lightning hail, tornado, donwburst/microburst

Front 72

What's needed to create a thunderstorm?

Back 72

Water vapor, Unstable air, lift mechanism

Front 73

What are the three types of thunderstorm cells?

Back 73

Towering cumulus stage, mature stage and dissipating stage

Front 74

What is a characteristic of the towering cumulus stage?

Back 74

Updrafts of 3,000 ft per minute

Front 75

What is a characteristic of the mature stage?

Back 75

Gust front, peak intensity, precipitation reaches surface

Front 76

What is a characteristic of the dissipating stage?

Back 76

Precipitation tapers off at the ends, cloud vaporizes

Lifecycle is about 30 mins

Front 77

What is a downburst?

Back 77

A strong downdraft, damaging winds on or near the ground. Vary from 1/2 mile to 10 miles, 120 kts winds

Front 78

What is a Microburst?

Back 78

A downburst that covers an area of 2.5 miles, 150 knot winds, 2 to 5 minutes

Front 79

What is a macroburst?

Back 79

A downburst that covers an area up to 10 miles, 120 kts, 5 to 30 minutes

Front 80

What three systems are designed to detect microbursts?

Back 80

LLWAS (Low-level wind shear alert system), TDWR (Doppler Radar, ASR-WSP (Airport Surveillance Radar Weather System processor)

Front 81

It may be impossible to recover from a ________ encountered at low altitude

Back 81

microburst

Front 82

When does Low level windshear occur?

Back 82

Wind 10 knots or more, 2,000 feet AGL

Front 83

When an aircraft in on approach, a shear from a tailwind to a headwind causes airspeed to ______, the nose to pitch _____, and the aircraft to _______ the glideslope

Back 83

airspeed increases, nose pitches up, , above the glideslope

Front 84

What are the three types of weather observations?

Back 84

Automated (auto-no observer), augmented (auto-observer), manual (observer)

Front 85

What are the three automated observation systems in the US?

Back 85

AWOS, ASOS, AWSS

Front 86

How often is a Metar transmitted?

Back 86

Scheduled reports, at least once per hour

Front 87

How often is a SPECI issued?

Back 87

Speci's are unscheduled, they contain all the data elements found in a METAR

Front 88

What four items do not need the word missing in a METAR?

Back 88

RVR, Present Weather group, Remarks, Report Modifier

Front 89

When else is the word missing added to a metar besides the four groups?

Back 89

When a portion of the METAR is unreadable or incorrect

Front 90

In an ICAO code, what is the first letter usually allocated to?

Back 90

Region or except for very large countries like the contiguous USA, where there are single letter country codes

Front 91

What is Alaska's ICAO prefix? Hawaii? Guam?

Back 91

Alaska is PA, Hawaii is PH, Guam is PG

Front 92

In a METARs wind group, the heading is relative to what direction?

Back 92

True north

Front 93

How is this said in a METAR?

0000KT

Back 93

Wind calm

Front 94

How is this read in a METAR?

VRB05KT

33037KT (300V010)

Back 94

Wind Variable at five

(Wind variable between three zero zero and zero one zero)

Front 95

What is the smallest and largest automated visibility that can be reported at the station?

Back 95

M1/4 SM (Visibility less than one quater)

Max is 10SM (Visibility one zero)

Front 96

What is prevailing visibility?

Back 96

Visibility of conditions at the station, At least half the horizon (180 degrees)

Front 97

When is RVR reported?

Back 97

When runway visibility is 1 SM or less and 6,000 ft or less

Front 98

In a METAR, what does M stand for?

What does P stand fore

Back 98

M is less than, P is more than

Front 99

At the Station, how many ______ miles?

In the vicinity (VC), ______ miles

Distant is ______ miles

Back 99

Station 0-5 miles

Vicinity 5-10 SM miles

Distant is more than 10 miles

Front 100

What are the METAR codes for "Sky partially obscured"?

Back 100

BKN000

FEW000

SCT000 all with coverage remarks in the remark section

Front 101

Define the descriptors....

MI,

PR,

BC,

DR,

BL,

SH,

TS,

FZ,

VC

Back 101

MI = Shallow

PR = Partial

BC = Patches

DR = Low drifting

BL = Blowing

SH = Shower

TS = Thunderstorm

FZ = Freezing Rain

VC = Vicinity

Front 102

METAR precipitation:

DZ,

RA,

SN,

SG,

IC,

PL,

GR,

GS,

UP

Back 102

DZ = Drizzle

RA = rain

SN = Snow

SG = Snow grains

IC = Ice crystals

PL = Ice pellets

GR = Hail

GS = Small hail

UP = Unknown precip

Front 103

Obscuration METAR codes

BR,

FG,

FU,

VA,

DU,

SA,

HZ,

PY

Back 103

BR = Mist

FG = Fog

FU = Smoke

VA = Volcanic ash

DU = Dust

SA = Sand

HZ = Haze

PY = Spray

Front 104

Additional METAR codes

PO,

SQ,

FC,

SS,

DS

Back 104

PO = Well developed Sandstorm

SQ = Squalls

FC = Funnel cloud, tornado (+), waterspout

SS = Sandstorm

DS = Dust-storm

Front 105

What is involved in the sky condition?

Back 105

Sky cover, layer of heights, ceiling and cloud types

Front 106

What is the sky cover?

Back 106

Amount of sky (celestial dome) hidden by clouds or obscurations

Front 107

What is an indefinite ceiling?

Back 107

Ceiling class applied when the ceiling value represents the upward visibility into a surface obscuration

Front 108

Contractions for SKY cover

VV,

SKC or CLR,

FEW,

SCT,

BKN,

OVC

Back 108

VV= Vertical visibility 8/8

SKC= Manual stations, clear below one two 1000

CLR= Auto stations, clear below one two 1000

FEW = Few clouds at 1/8 to 2/8 coverage

SCT= ______ Scattered 3/8 to 4/8 coverage

BKN = Broken 5/8, 6/8, 7/8 coverage

OVC = Overcast 8/8 coverage

Front 109

What does the following indicate in a METAR regarding sky coverage?

000

///

Back 109

000 = Layer is 50 feet or less AGL

/// = Layer is below the station level

Front 110

When do you call ceiling on a METAR?

Back 110

Before Broken or overcast ( Lowest layer aloft)

Front 111

What does DSNT mean in a METAR Remarks' section?

Back 111

Weather beyond 10 SM of the observation point

Front 112

What is the difference between a funnel cloud, tornado and waterspout?

Back 112

FC does not touch the ground

tornado touches the ground

waterspout is a tornado over water

Front 113

What is Peak wind speed in the remarks section of a metar?

Back 113

Instantaneous wind speed that exceeded 25 knots since the last METAR

Front 114

How do you read the following peak wind line on a METAR?

PK WND 33048/22

Back 114

Peak wind 3,3,0 at 4,8 occurred at 2,2 past the hour

Front 115

What are the requirements of variable prevailing vis?

VIS 1V3

Back 115

Vis less than 3 SM, rapidly increases and decreases by 1/2 mile

Visibility variable between one and three

Front 116

What is a characteristic of sector visibility?

Back 116

Visibility of a direction at least 45 degrees in the horizon

Front 117

How of often does lightning frequency apply?

ONCL

FRQ

CONS

Back 117

Occasional = less than 1 flash per minute

Frequent = 1 to 6 flashes per minute

Continuous= More than 6 flashes per minute

Front 118

In a METAR, if GS (small hail) is coded in the body of the report, what needs to be coded in the remarks?

Back 118

Nothing, hail size (per 1/4 inch) is only reported with the code GR

Front 119

What can virga predict?

Back 119

The beginning of a dry microburst or icing at altitude

Front 120

What is ceiling variable?

CIG 007V019

Back 120

It is a ceiling of less than 3,000 feet that rapidly changes

Ceiling variable between 7 hundred and one thousand 9 hundred

Front 121

Which clouds indicate mountain waves which can produce severe to extreme turbulence?

Back 121

ROTOR CLD, SCSL, ACSL, CCSL

Stratocumulus standing lenticular

altocumulus standing lenticular

cirrocumulus standing lenticular

Front 122

When is the snow rising rapidly remark used?

Back 122

When snow depth has increased 1 inch or more past the hour

Front 123

What is a TAF?

Back 123

A TAF is a forecast of expected weather conditions within 5 SM of an airport (terminal use)

Front 124

Who issues a TAF and how often is a TAF issued?

Back 124

Every 6 hours. 0000, 0600, 1200, 1800

Issued by the NWS

Front 125

What is included and what is not included in a TAF?

Back 125

Wind

Visibility

Significant weather

Cloud and obscuration

Low level windshear

Not included is the altimeter, dew/temp and remarks

Front 126

For how long are TAFs valid?

Back 126

24 hours

30 hours for international traffic

Front 127

What are the keywords of TAF changes?

FM

TEMPO

PROB 30

Back 127

FM (Rapid and significant) All elements included again

TEMPO (temp fluctuations) Only changes are updated

PROB 30 (Low probability 30% of precip)

Front 128

What are the 3 types of in-flight advisories?

Back 128

SIGMET, CONVECTIVE SIGMET, and AIRMET

Front 129

What is SIGMET and when is it issued?

Back 129

Refers to significant weather, safety to the jet, area of 3,000 miles

Thunderstorms

Severe Icing

Severe turbulence

Tornadoes

Duststorms,

Sandstorms, Ash

Front 130

How long is a SIGMET valid for?

Back 130

4 hours in the US, 6 hours outside US

Front 131

When are convective Sigmets issued?

Back 131

Issued when a severe thunderstorm is forecast, only in the US

Severe TS must have:

Winds greater than 50 knots

Hail greater than 3/4 inch in size

Tornado

Front 132

How long are convective SIGMETs valid for?

Back 132

2 hours

Front 133

What is an AIRMET and how long is it valid for?

Back 133

In flight advisory concerning weather, issued on a scheduled basis

Valid for 6 hours

Front 134

What type of AIRMETs exist and what are they for?

Back 134

SIERRA (IFR Weather), TANGO (Turbulence, 30 knot winds, winshear), ZULU (Moderate Icing and freezing)

Front 135

What is the CWA?

Back 135

an unscheduled weather advisory issued for ATC use to alert pilots of anticipated adverse weather in the next 2 hours

Front 136

What is not a flight planning product because of its short lead time?

Back 136

A CWA

Front 137

What severe weather is included in a CWA?

Back 137

Thunderstorms

Icing,

turbulence (moderate to severe)

heavy precip

freezing precip

low IFR (ceiling less than 500 AGL)

Wind more than 30 knots

Wind shear

DS SS VA

Front 138

What is a MIS and for whom does it apply?

Back 138

It is an unscheduled anticipated weather report written in plain language for ARTCC and TMU personnel

Front 139

Which report is not intended for pilot?

Back 139

MIS (Meteorological impact statement)

Front 140

How long does a MIS (Meteorological impact statement) last for?

Back 140

Up to 2 days

Front 141

The Wind and Temperature aloft (FB) is used by ATC to help ________

Back 141

Avoid clear air turbulence created by crosswinds

Front 142

What is a PIREP?

Back 142

Pilot weather reports in-flight in areas where there are no weather stations

Front 143

What are the two classes of PIREPs?

Back 143

Urgent (UUA) and Routine (UA)

Front 144

What is in an Urgent PIREP?

Back 144

Tornadoes, severe or extreme turbulence, Severe icing, hail, LLWS, VA, any other weather phenomena hazardous for flight

Front 145

What do towers and TRACONS use PIREPs for?

Back 145

Expedite traffic flow in the vicinity of the airport, avoid hazardous weather

Front 146

What do FSSs use PIREPs for?

Back 146

Brief pilots and issue in-flight weather advisories

Front 147

What does ARTCC use PIREPs for?

Back 147

Expedite the flow of en-route traffic

Front 148

What does the NWS use PIREPs for?

Back 148

Verify or amend forecasts, pilot weather briefings, issue advisories

Front 149

What are the requirements to solicit PIREPS? *

Back 149

Ceiling at or below 5,000

5 miles Visibility

Ash (Volcanic)

Braking action

Icing (light or more)

Thunderstorms

Turbulence (moderate or more)

Windshear

Front 150

What does a PIREP have to contain?

Back 150

Aircraft location, altitude, type of aircraft and at least one other element

Front 151

When PIREPs include turbulence, what needs to be included?

Back 151

In clouds or clear air, type and intensity of turbulence

Front 152

When PIREPs include icing, what needs to be included?

Back 152

Type and intensity, air temperature

Front 153

What is the PIREP form and what are the elements on the PIREP form called?

Back 153

FAA 7110.2 and Text element indicators

Front 154

Cloud layers on PIREPs are reported in what height?

Back 154

Hundreds of feet MSL

Front 155

How do you write unrestricted visibility on a PIREP?

Back 155

FV99SM