Weather Sources Products and Interpretation Flashcards

Question 1

Q

Justify your go/no-go decision. In other words, I want you to walk me through all the weather charts that you used during your planning for this VFR cross-country flight and prove to me that you won’t encounter any adverse weather. If there is adverse weather and you’re making a go decision, show me that you’ve competently planned around it

Answer

A

Typical charts that applicants use: Radar Summary, Surface Analysis, Convective Outlook, Low Level Significant Weather Prognostic, Winds Aloft, METARs and TAFs of all stations along the flight route, Graphical Area Forecast charts for the flight full duration and range of altitudes, PIREPs, various icing and freezing level charts.

Question 2

Q

Provided the weather is unavoidable, what kind of weather would cause you to make a no-go decision for this VFR flight?

Answer

A

Thunderstorms or any other convective activity, high winds (including windshear), excessive turbulence, low cloud ceilings/visibility, icing conditions, heavy precipitation.

Question 3

Q

Take me through the weather charts and sources that you used to verify that we won’t encounter any such weather (note: there are many options/answers here).

Answer

A

● Thunderstorms/convection: Radar Summary, Graphical Area Forecast, METAR/TAF, PIREP, Convective Outlook, Convective SIGMET. ● High winds: Winds Aloft, Surface Analysis, METAR/TAF, Graphical Area Forecast, AIRMET/SIGMET. ● Turbulence: AIRMET/SIGMET/Convective SIGMET, Graphical Area Forecast, Low Level Prog. ● IMC: Graphical Area Forecast, METAR/TAF, Low Level Prog. ● Low cloud ceiling: Graphical Area Forecast, METAR/TAF. ● Potential icing: Winds Aloft and/or Freezing Level charts to determine freezing level; Graphical Area Forecast and METAR/TAF to determine location of visible moisture. ● Heavy precip: Radar Summary, METAR/TAF, Graphical Area Forecast.

Question 4

Q

How do you determine cloud coverage and visibility beyond the 5 sm range of a TAF?

Answer

A

Use the GFA tool.

Question 5

Q

What are the three types of weather products?

Answer

A

Observation, forecast, and analysis

Question 6

Q

When is the Radar Summary (Radar Coded Message) chart issued, and what is its valid time?

Answer

A

Issued every 30 minutes, 15 and 45 minutes past the hour (used to be issued hourly). It’s an observation, so it’s valid at the time observed, i.e. the time stated on the chart: 04/26/2015 at 2315Z.

Question 7

Q

What type of equipment generates radar observations of weather in the U.S.?

Answer

A

Doppler radars, i.e. NEXRAD (Next Generation Weather Radar).

Question 8

Q

How does the doppler/nexrad radar work

Answer

A

It sends out a signal that reflects (or echoes) off of precipitation. The radar then measures the reflective power in terms of decibels (dBZ). The higher the reflectivity, the more intense the precipitation.

Question 9

Q

Would you expect to encounter the strongest precipitation in the green or pink regions on the radar summary chart?

Answer

A

Pink, those represent the highest decibels.

Question 10

Q

What information do the decibles in the radar summary chart provide?

Answer

A

Location of precipitation, precipitation intensity, precipitation echo tops, cell movement speed and direction.

Question 11

Q

Which direction is the cell in Montana with the 180 echo top moving, and how fast?

Answer

A

Moving north at 15kts.

Question 12

Q

What does a flag on a wind barb indicate?

Question 13

Q

Are echo tops the same as cloud tops?

Answer

A

No, echo tops represent the highest altitude containing precipitation. Cloud tops are generally slightly above this.

Question 14

Q

Nevada is all white . . . does this mean that there are no clouds in Nevada?

Answer

A

No, this chart does not show cloud coverage, it shows precipitation. The colored areas will certainly have clouds, as precipitation needs to fall from something; but just because there is no precipitation depicted doesn’t mean there are no clouds.

Question 15

Q

Name some limitations associated with radar-generated weather products?

Answer

A

● Beam overshoot/undershoot: some of the Doppler radars that generate this image are on mountain tops, and the radars don’t look down . . . so any precipitation occurring below the elevation of the radar equipment won’t be detected.

● Beam blockage: terrain can block the radar beam.

● Ground clutter: echo returns from trees, buildings, or other objects on the ground are usually automatically removed from the image. Usually.

● Anomalous propagation (AP): a pattern of ground echoes caused by super-refraction of the radar beam. Super-refraction causes the radar beam to bend downward and strike the ground.

● Ghosts: echoes in apparently clear air caused by a “cloud” of point targets.

● Angels: echoes caused by a physical phenomenon not discernible by the eye at the radar site, such as bats, birds, or insects.

● Other non-meteorological phenomena: E.g. wind farms, or smoke from forest fires.

Question 16

Q

Question 17

Q

What are some additional limitations associated specifically with the Radar Summary Chart?

Answer

A

AC00-45H says that tops above 50,000ft can be disregarded, that they are likely a mistake. Also, this chart is merely a snapshot of the weather at a specific time – weather changes rapidly, so this chart should be considered highly supplemental to any preflight weather briefing.

Question 18

Q

What’s a major concern about flying through a region showing high echo tops?

Answer

A

Stronger updrafts, possibly leading to more severe convective activity.

Question 19

Q

How often is the Wind and Temperature Aloft Forecast (FB) issued, and when is it valid?

Answer

A

The forecast is now produced 4 times/day (PHAK wrongly still says twice daily). The wind and temperature information depicted in the forecast are predicted to occur at the valid time specified in the header; however, the information CAN BE USED for flights occurring within the specified “for use” time range.

Question 20

Q

Are the wind directions in the winds aloft chart true or magnetic

Question 21

Q

What does 9900 mean in the winds aloft chart?

Answer

A

Light and variable.

Question 22

Q

Why are wind and temperature not listed for SIY at 3000ft?

Answer

A

Wind is not listed within 1,500 of a location’s elevation. Temperatures are only provided for the 6,000 ft level and above. Use the METAR/TAF to interpolate winds and temps at altitudes near field elevation. Surface friction makes the wind predictions difficult.

Question 23

Q

Why is no temperature listed for BIH at 6,000 ft?

Answer

A

Temperatures are not listed within 2,500 ft of a location’s elevation (and again, never for the 3,000 ft elevation).

Question 24

Q

What wind and temperature would you expect in the vicinity of the FOT station at 34,000ft?

Answer

A

Wind from 320 at 105 kts, temperature -47 degrees Celsius.

Question 25

Q

What tells you that the temperature is negative in the winds aloft chart?

Answer

A

The header states that all temps above FL240 are negative.

Question 26

Q

Would you expect stable or unstable air flying in SEA below 12,000ft? Why?

Answer

A

Stable. Temperature drops of 2 degrees or fewer for every 1,000 ft of increased altitude is 100 generally indicative of stable air. In the case of SEA, the temperature drops by only 8 degrees between 6,000 and 12,000 ft. Also noteworthy, the wind velocities are not significant.

Question 27

Q

What type(s) of altitudes are displayed on this forecast?

Answer

A

MSL below 18,000 ft; pressure altitude (flight levels) starting at 18,000 ft and above.

Question 28

Q

What are the issue and valid times for the Surface Analysis Chart?

Answer

A

This chart is issued every 3 hours, once analysis of the observed weather is complete. The valid times are either 00, 03, 06, 09, 12, 15, 18, or 21 UTC. In the case of the chart above, the weather shown on the chart is valid for 2100Z.

Question 29

Q

What type of chart is this?

Answer

A

Analysis.

Question 30

Q

What do the maroon solid lines represent on the surface analysis chart?

Answer

A

Isobars. These connect areas of equal sea level pressure.

Question 31

Q

Question 32

Q

if the pressure on the surface analysis chart reads “1014”, say, that does not indicate station pressure?

Answer

A

Correct, it’s station pressure adjusted down to sea level.

Question 33

Q

What kind of weather would you expect to encounter on the surface analysis chart in areas where the bars are close together? Why?

Answer

A

High winds. Isobars close together represent a steep pressure gradient. This causes the air to be more inclined to move.

Question 34

Q

What does the orange scalloped line extending up from Mexico continuing through the middle of the U.S. represent?

Answer

A

Dry line.

Question 35

Q

What’s a dry line:

Question 36

Q

What does the dashed orange line extending up from Florida along the east coast represent?

Answer

A

A trough.

Question 37

Q

What’s a trough and what kind of weather would you expect to encounter flying along one?

Answer

A

It’s an elongated area of relatively low pressure. Expect generally poor weather, as low pressure systems involve updrafts which are conducive to convective activity.

Question 38

Q

Question 39

Q

The station plot in south western California is a blue circle surrounded by another blue circle. What does this symbol indicate?

Answer

A

Winds calm.

Question 40

Q

Surrounding the light-and-variable symbol, what do the red “81,” green “42,” orange “137,” and orange “\” with a “-7” to the right of it, all represent?

Answer

A

Temperature 81 degrees F, dewpoint 42 degrees F, pressure 1013.7 mb, pressure continuously fell over the previous 3 hours by .7 mb.

Question 41

Q

What does an “M” inside a station plot circle indicate?

Answer

A

Missing cloud observation.

Question 42

Q

In northern Georgia there is a pink “R” just to the left of the high pressure system. What does this symbol indicate?

Answer

A

Thunderstorm.

Question 43

Q

What kind of chart is a Low Level Significant Weather Prognostic

Answer

A

Forecast.

Question 44

Q

What kind of weather is depicted on this chart?

Answer

A

(Just read from the legend on the bottom of the chart.) IMC, MVFR, moderate or greater turbulence, freezing levels.

Question 45

Q

What are the issue and valid times for this chart?

Answer

A

Issued 4 times/day, valid at the specific times listed on the charts. The left and right panels will always be 12 hours apart.

Question 46

Q

On the left panel, what does the “/” after the “150” in Idaho mean?

Answer

A

The symbol means down to the surface . So the moderate turbulence descends from 15,000 ft MSL down to the surface.

Question 47

Q

Provided your ETD matches the valid time on the chart, can you take off without being on an IFR flight plan out of an airport surrounded by one of the blue scalloped lines?

Answer

A

Yes, marginal VMC is still 3 sm + 1,000 ft ceiling or greater.

Question 48

Q

What if your airport is surrounded by a red line can you take off without being on an IFR flight plan?

Answer

A

No, must be on an IFR flight plan.

Question 49

Q

Let’s say you’re flying from Nevada to Colorado. You think it would be better to get your freezing level off of this chart or the Winds Aloft?

Answer

A

Definitely Winds Aloft, as it will indicate the precise freezing level for your location. This chart, on the other hand, requires heavy interpolation.

Question 50

Q

The dashed orange line represents areas with “moderate or greater turbulence.” What symbol does this chart use to differentiate severe and extreme turbulence from moderate?

Answer

A

Same dashed orange line, except the altitude shows more of the little symbols stacked up above it in order to indicate more intense turbulence.

Question 51

Q

What kind of chart is a Convective Outlook?

Answer

A

Forecast.

Question 52

Q

What are its issue and valid times for the convective outlook chart?

Answer

A

The Day 1 Outlook is issued 5 times/day, with the valid time specified on the chart. (Other Convective Outlooks show forecasts that extend up to 8 days, and those are issued less frequently.)

Question 53

Q

What weather information does the convective outlook chart provide?

Answer

A

It shows 2 things:

1) the probability of severe convection (tornados, wind gusts 50 kts or greater, or hail 1 inch in diameter or greater), and
2) non-severe (general) convection.

Question 54

Q

What do the colors represent on the convective outlook chart?

Answer

A

The light green TSTM areas represent non-severe (general) convection. The rest of the colors indicate areas of marginal, slight, enhanced, moderate, and high probabilities of severe thunderstorms occurring. METAR

Question 55

Q

What kind of weather product is a METAR?

Answer

A

Observation.

Question 56

Q

When is the metar issued and what is its valid time?

Answer

A

Issued hourly, usually toward the end of the hour, valid at the time of observation specified on the METAR.

Question 57

Q

What does METAR stand for?

Answer

A

Aviation Routine Weather Report (the acronym comes from the French translation of Aviation Routine Weather Report).

Question 58

Q

What kind of weather product will be released in place of a METAR in the event of a significant weather change?

Answer

A

A Special Weather Report, aka SPECI.

Question 59

Q

Does this SFO METAR show VMC or IMC conditions? Why?

KSFO 121756Z 26020G27KT 200V290 R17L/2600FT VV002 FEW005 SCT015

SCT100 BKN200 18/-12 A3009 RMK AO2 RAB46 PK WND 27029/1729

WS010/18040KT LTG DSNT S OCNL LTGICCC SE CB DSNT S TS SE MOV S

SLP191 T01780117 $

Answer

A

IMC, due to visibility (2,600 ft) being less than 3sm, as well as the ceiling (200 ft) being less than 1,000 ft.

Question 60

Q

What is the ceiling?

KSFO 121756Z 26020G27KT 200V290 R17L/2600FT VV002 FEW005 SCT015

SCT100 BKN200 18/-12 A3009 RMK AO2 RAB46 PK WND 27029/1729

WS010/18040KT LTG DSNT S OCNL LTGICCC SE CB DSNT S TS SE MOV S

SLP191 T01780117 $

Question 61

Q

Are the reported winds true or magnetic on the METAR?

Question 62

Q

Is “BKN200” in MSL or AGL?

KSFO 121756Z 26020G27KT 200V290 R17L/2600FT VV002 FEW005 SCT015

SCT100 BKN200 18/-12 A3009 RMK AO2 RAB46 PK WND 27029/1729

WS010/18040KT LTG DSNT S OCNL LTGICCC SE CB DSNT S TS SE MOV S

SLP191 T01780117 $

Answer

A

AGL. Clouds are always AGL on METARs and TAFs.

Question 63

Q

hat is the gust factor?

KSFO 121756Z 26020G27KT 200V290 R17L/2600FT VV002 FEW005 SCT015

SCT100 BKN200 18/-12 A3009 RMK AO2 RAB46 PK WND 27029/1729

WS010/18040KT LTG DSNT S OCNL LTGICCC SE CB DSNT S TS SE MOV S

SLP191 T01780117 $

Answer

A

W7 kts (difference between sustained and gusting winds).

Question 64

Q

What does “A02” indicate?

KSFO 121756Z 26020G27KT 200V290 R17L/2600FT VV002 FEW005 SCT015

SCT100 BKN200 18/-12 A3009 RMK AO2 RAB46 PK WND 27029/1729

WS010/18040KT LTG DSNT S OCNL LTGICCC SE CB DSNT S TS SE MOV S

SLP191 T01780117 $

Answer

A

The station is automated with a precipitation discriminator.

Answer 57

A

Eastbound - the wind is coming FROM 270.

Answer 58

A

Clouds, possibly fog and mist . . . just more visible moisture.

Answer 59

A

● 200V290: wind variable between 200 and 290 degrees.

● R17L/2600FT: runway visual range for Runway 17L is 2,600 ft.

● VV002: vertical visibility is 200 ft (ceiling is indefinite, so vertical visibility becomes the

ceiling).

● RAB46: rain began 46 minutes past the hour.

● PK WND 27029/1729: peak wind was 270@29 kts occurring at 17:29Z.

● WS010/18040KT: wind shear at 1,000 ft: 180@40 kts. Put differently, the surface wind of 260@20 gusting 27 shears to 180@40 at 1,000 ft.

● LTG DSNT S OCNL LTGICCC SE CB DSNT S TS SE MOV S: lightning distant south, occasional lightning in-cloud and cloud-to-cloud to the southeast, cumulonimbus clouds in the distant south, thunderstorm to the southeast moving south.

● SLP191: sea level pressure is 1019.1

● T01781117: more precise temperature and dewpoint: temperature is 17.8, dewpoint -11.7.

● $: maintenance needed.

Answer 60

A

A forecast, it’s in the name.

Answer 61

A

Issued 4 times/day (000Z, 0600Z, 1200Z, and 1800Z), valid for either 24 hours or 30 hours, as depicted on the TAF.

Answer 62

A

Terminal Aerodrome Forecast.

Answer 63

A

5 sm from the center of the runway complex.

Answer 64

A

Means that the indicated weather is expected to last for less than 1 hour, and in total, less than half the time indicated.

Answer 65

A

The only times IMC is forecast to occur is between 18:00 - 19:00 on the 12th. After 19:00 the weather returns to VMC.

Answer 66

A

Respectively: thunderstorm with light rain, mist, showers in the vicinity.

Answer 67

A

FG. Fog is for < 5/8 SM; mist (BR) is used for > 5/8 SM.

Answer 68

A

30% probability that the weather between 17:00Z and 18:00Z on the 13th will drop to 3 SM vis, thunderstorms with moderate rain, and broken cumulonimbus clouds at 3,000 ft AGL. AIRMET (WA), SIGMET (WS), Convective SIGMET (WST)

Answer 69

A

AIRMETs, SIGMETs, and Convective SIGMETs.

Answer 70

A

SIGMET, Convective SIGMET, AIRMET, and Center Weather Advisory (CWA).

Answer 71

A

WWs supplement those 4 inflight aviation weather advisories.

Answer 72

A

They are issued by the Aviation Weather Center (AWC) and are periodically announced by ATC to pilots in flight. Pilots can also get these while enroute from an FSS. They are obtainable on the ground through virtually all approved aviation weather sources.

Answer 73

A

All, although they’re certainly more pertinent for smaller aircraft and pilots without instrument ratings. Put differently, an AIRMET details significant enroute weather phenomena that could be of interest to all aircraft, but potentially hazardous to small aircraft.

Answer 74

A

An AIRMET is a forecast that describes significant weather occurring at intensities lower than weather requiring the issuance of a SIGMET. Generally, an AIRMET is issued for moderate weather, whereas a SIGMET is issued for severe or greater weather.

Answer 75

A

Airmen’s Meteorological Information.

Answer 76

A

Changes in altitude and/or attitude occur but the aircraft remains in positive control at all times. Usually variations in indicated airspeed will occur. Occupants feel definite strains against seat belts or shoulder straps. Unsecured objects are dislodged. Food service and walking are difficult.

Answer 77

A

Issued every 6 hours, valid for 6 hours. Includes an outlook describing weather over the next 6 hours. Unscheduled amendments and updates are issued as required.

Answer 78

A

For all of the following, when the weather phenomena are occurring or are expected to occur over an area of at least 3,000 square miles:

● Tango: moderate turbulence, sustained surface wind greater than 30kts. Non-convective low-level windshear potential below 2,000 ft AGL.

● Sierra: extensive IFR conditions (less than 3sm vis or 1,000 ft ceiling) and/or mountain obscuration.

● Zulu: moderate icing with freezing level heights.

Answer 79

A

Possibly, although probably not. I would investigate further to see if the turbulence exceeded my personal mins. If able, I would plan around the affected area.

Answer 80

A

All aircraft, but unlike AIRMETs, SIGMETs indicate weather that is potentially hazardous to all aircraft.

Answer 81

A

Significant Meteorological Information.

Answer 82

A

as necessary, valid for up to 4 hours, except that SIGMETs involving tropical cyclones and volcanic ash are valid for 6 hours. Updates and corrections issued as necessary.

Answer 83

A

For all of the following, when the non-convective weather phenomena are occurring or are expected to occur over an area of at least 3,000 square miles:

● Severe or extreme turbulence or clear air turbulence not associated with thunderstorms.

● Severe icing not associated with thunderstorms.

● Widespread dust storm or sandstorm lowering surface visibilities to below 3 miles.

● Volcanic ash.

Answer 84

A

Severe turbulence causes large, abrupt changes in altitude and/or attitude usually accompanied by large variations in indicated airspeed. Aircraft may be momentarily out of control.

Answer 85

A

I would plan around it. If unable, I’d make a no-go decision.

Answer 86

A

The key word/differentiator is “convective” - so unlike SIGMETs, Convective SIGMETs sound the alarm on more extreme weather associated with thunderstorms . To quote the AIM directly: a Convective SIGMET may be issued for any convective situation that the forecaster feels is hazardous to all categories of aircraft.

Answer 87

A

Issued hourly 55 minutes past the hour, updated as required. Valid for up to 2 hours.

Answer 88

A

SEAT

● Severe thunderstorms due to:

Surface winds greater than or equal to 50 kts.
Hail at the surface greater than or equal to ¾ inches in diameter.
Tornadoes.

● A line of thunderstorms.

● Embedded thunderstorms.

● Thunderstorms producing precipitation greater than or equal to heavy precipitation affecting 40 percent or more of an area of at least 3,000 square miles.

Answer 89

A

No, any Convective SIGMET implies severe or greater turbulence, severe icing, and low-level wind shear.

Answer 90

A

This is an unscheduled inflight weather advisory used to supplement AIRMETs/SIGMETs/Convective SIGMETs. The FAA describes a CWA as a “nowcast” for conditions developing in the next 2 hours. Graphical Area Forecast (GFA)

Answer 91

A

The GFA provides aviation weather information to give users a complete visual picture of the weather that may impact their flights. Users can select for virtually any type of weather, time, altitude, and flight path.

Answer 92

A

continuously, valid for the selected times. Users can select FORECAST for a range of valid times that extend 15 hours into the future, or select OBSERVATION for valid times in the previous 14 hours.

PIREP

Answer 93

A

Nearest station: KCMH, message type: routine (non-urgent) report. /

Location: weather occurred 10DME out on the APE 230 degree radial. /

Time: time that reported weather occured was 15:16Z. /

Altitude: altitude where the weather was encountered is 8,500 ft MSL. /

Aircraft type: type of aircraft reporting the PIREP is a BE20. /

Sky condition: broken at 6,500 ft MSL. /

Flight visibility and weather: 3 SM due to haze and smoke. /

Air temperature: 20 degrees. /

Turbulence: light. /

Icing: moderate mixed iced between 4,000 - 5,000 ft MSL. /

Remarks: low-level wind shear, pilot reported minus (a loss of) 15 kts between the surface and 3,000 ft during climb out from runway 22 at CMH airport.

Answer 94

A

ATC or an FSS.

Answer 95

A

On the ground you can use Foreflight, aviationweather.gov, 1800wxbrief.com, or call a briefer. In the air you can talk to ATC or an FSS.

Answer 96

A

PIREPs can be filed enroute with either ATC or an FSS. The AIM advises against being overly concerned with strict format or phraseology: “The important thing is that the information is relayed so that other pilots may benefit from your observation.” Pilots should simply give position, time, altitude, type aircraft, and a description of the weather (sky cover, flight vis, precip, restriction to vis, temp, wind direction and strength, turbulence, icing, additional remarks).

Answer 97

A

MSL, unless noted otherwise.

Answer 98

A

● Standard briefing: a standard weather briefing provides a complete picture of the weather and is the most detailed of all briefings. It includes adverse conditions, VFR flight not recommended (if applicable), a synopsis, current conditions, en route forecast, destination forecast, winds and temps aloft, NOTAMs, prohibited areas and SFRAs, ATC delays, and other information specifically requested by the pilot. This type of briefing should be obtained prior to the departure of any flight.

● Abbreviated briefing: this is a shortened version of the standard briefing that should be requested when a departure has been delayed or when specific weather information is needed to update a previous standard briefing.

● Outlook briefing: this briefing should be requested when a planned departure is 6 or more hours away. It provides initial forecast information that is limited in scope, but that can influence decisions regarding route of flight, altitude, and ultimately the go/no-go decision. A follow-up standard briefing prior to departure is advisable.

Brainscape's Knowledge GenomeTM

Weather Sources Products and Interpretation Flashcards

Brainscape's Knowledge Genome^TM