L13 Aviation Weather Reports

Flashcards based on Aviation Weather Reports lecture notes.

What is the expected outcome of a pilot's knowledge of meteorology?

Enable the pilot to make the best of available information and recognize/avoid hazardous weather situations.

Which ICAO annex sets out the standards for weather reporting and forecasting?

SARPS Annex 3

Which organization ensures that weather reporting standards are implemented for aviation?

World Meteorological Organization (WMO)

What are the two World Area Forecasting Centres (WAFC)?

US NOAA and UK Met Office

What weather forecasts do WAFCs prepare?

Upper winds, temperature, humidity, tropopause temperature, cumulonimbus cloud formations, icing, and turbulence.

What is a weather report?

A factual statement of actual weather conditions at a stated place and time.

What is a weather forecast?

A prediction of the expected weather situation during a set period.

Where are official aviation weather reports provided from?

Aeronautical meteorological stations

What is the most basic source of weather observation?

Surface observation

What is a 'Meteorological Actual Report' abbreviated as?

METAR

Who or what provides METAR reports?

Trained meteorological observers or automatic systems

What type of report is issued if specific aviation criteria are met after 10 minutes following an improvement?

Special report of meteorological conditions (SPECI)

What is the name of the instrument package suspended below a balloon to measure atmospheric conditions?

Radiosonde

What does a radiosonde transmit measurements of?

Position, altitude, pressure, temperature, relative humidity, wind speed and direction.

What are the two basic formats of satellite imagery?

Visible and infrared (IR).

What is a visible satellite image?

A black-and-white photograph taken from a satellite.

What is an infrared (IR) image based on?

Temperature differences.

What processing is applied to satellite images?

Latitude and longitude grid lines, coastlines, and adjustments for daylight amount.

What do weather radar systems detect?

Detect areas and intensity of precipitation.

What does the radar system pinpoint?

Active thunderstorms based on their electrical activity.

How long are weather radar images often delayed by on the internet?

Up to 30 minutes.

What is modern ATC radar designed to do?

Filter out weather 'clutter'.

What are pilot-reported weather observations called?

AIREPs

What conditions require immediate reporting in a European FIR?

Severe icing or turbulence, moderate turbulence in transonic or supersonic flight, and other met conditions affecting safety.

Who disseminates pilot-reported wind shear information to other pilots?

Meteorological Watch Offices (MWO)

What produces a METAR aviation weather report?

Meteorological Watch Office (MWO)

How often are METARs compiled in the UK?

Every 30 or 60 minutes at fixed times.

What does the first element in a METAR indicate?

ICAO four letter code for the airfield.

How is the date and time of observation specified in a METAR?

Day of the month, hours and minutes UTC

What does 'AUTO' indicate in a METAR?

Fully automated observation with no human intervention.

How is surface wind direction given in a METAR?

Degrees True, rounded to the nearest 10 degrees

What units are used for windspeed in a METAR?

Knots (KT), kilometres per hour (KMH) or metres per second (MPS).

How is calm wind indicated in a METAR?

00000

How is variable wind direction indicated in a METAR?

VRB

What is prevailing visibility?

The visibility within at least half the horizon circle or half of the aerodrome surface.

How is the direction of the lowest visibility reported in a METAR?

One of the eight points of the compass.

What indicates a visibility of 10 km or more in a METAR?

9999

What indicates a visibility of less than 50 m in a METAR?

0000

When is Runway Visual Range (RVR) reported?

When the horizontal visibility or RVR is less than 1500 m.

In a METAR, what does FEW mean in relation to cloud cover?

1 to 2 oktas

In a METAR, what does SCT mean in relation to cloud cover?

3 to 4 oktas

In a METAR, what does BKN mean in relation to cloud cover?

5 to 7 oktas

In a METAR, what does OVC mean in relation to cloud cover?

8 oktas

What types of cloud are reported in a METAR?

Cumulonimbus (CB) and Towering Cumulus (TCU)

What does NSC mean in a METAR?

No significant cloud.

What does VV followed by digits indicate in a METAR?

Vertical visibility in hundreds of feet.

What does QNH represent in a METAR?

Pressure rounded down to the next whole millibar.

What does recent weather indicate in a METAR?

Operationally significant weather observed since the previous observation.

What does the trend section of a METAR indicate?

Forecast of significant changes in conditions during the two hours after the observation time.

What does BECMG (trend abbreviation) stand for?

Becoming

What does TEMPO (trend abbreviation) stand for?

Temporary

What does FM (trend abbreviation) stand for?

From

What does TL (trend abbreviation) stand for?

Until

What does AT (trend abbreviation) stand for?

At

In automatic METARs, what does NDV stand for?

No directional variation reported

In an automatic METAR, what does // indicate?

Present weather cannot be detected.

In an automatic METAR, what does UP stand for?

Unidentified precipitation

In an automatic METAR, what does FZUP stand for?

Freezing unidentified precipitation

In an automatic METAR, what does /// after a cloud group mean?

The system cannot detect towering Cumulus or Cumulonimbus

In an automatic METAR, what does NCD mean?

No Cloud Detected

In an automatic METAR, what does //// for visibility indicate?

Lack of measuring equipment causes failure in visibility

In an automatic METAR, what does REUP mean?

Recent unidentified precipitation.

In an automatic METAR, what does ////////// for cloud indicate?

Lack of measuring equipment causes failure in cloud

Once flight begins, what becomes one of the best instruments for checking in-flight weather?

Pilot's own eyes

What radio broadcast transmits the METARS of larger airfields?

VOLMET

What is the VOLMET service?

A recorded broadcast giving the METARS for a group of around ten airports.

What is a 'TREND' in a VOLMET report?

Expected change in conditions during the two-hour period following the time of the METAR.

What does ATIS stand for?

Automatic Terminal Information Service

What frequencies does ATIS broadcast on?

VHF frequency or frequency of a nearby VOR navigational beacon

When are ATIS broadcasts useful?

Checking en route or alternate airfields during a flight

What does ICAO stand for?

International Civil Aviation Organisation

What weather condition, if encountered, should be reported immediately over the radio to the ground station?

Wind Shear

What does AIP stand for?

Aeronautical Information Publication

What is the aim of the meteorology course?

Ensure pilots make the best of available weather information and avoid potentially hazardous weather.

What does SARPS stand for?

International Standards and Recommended Practices

Why was the World Area Forecasting System (WAFS) developed in the 1980s by ICAO?

To include the provision of upper-air forecasts

Besides upper winds, what other temperature and humidity forecasts do WAFCs prepare?

Upper-air temperature and humidity

Besides cumulonimbus clouds and icing, what areas do WAFCs forecast?

Areas where turbulence (both clear-air and in-cloud) is forecast

What should pilots always be aware of when receiving meteorological information?

A pilot should always be absolutely clear as to whether the piece of weather information they have been given is a report, i.e. the actual weather, or a forecast, e.g. a prediction.

Why do meteorologists use radiosonde information?

To confirm predictions and aid future forecasting.

Thick _ tends to show as white on a visible image.

Cloud

Ground covered with _ may be confused with thick cloud on a visible image.

Snow

A satellite cannot produce a _ at night.

Visible image

Very low _ may have nearly the same temperature as the surface on an infrared (IR) image, making it very difficult to distinguish.

Fog

Satellite images should only be used in conjunction with other _ or significant weather information.

Synoptic

Weather radar images are widely available via the Internet although they are often delayed by up to 30 minutes rather than being _.

Real-time

AIREPs are not normally required in _ (FIRs).

European Flight Information Regions

Moderate turbulence, hail or cumulonimbus clouds are encountered in _ or supersonic flight.

Transonic

In a METAR, what is the wind?

18012KT 130V230

In Aviation, what visibility is 10 km or more?

9999

In Aviation, what would you call the prevailing visibility?

8000N

In aviation, what are Showers in the Vicinity?

VCSH

In aviation weather reports, what does Scattered at 1400 feet Cumulonimbus stand for?

SCT014CB

In aviation weather, what is the air temperature and dewpoint?

20/11

In aviation weather, what is QNH?

Q1006

In aviation weather reports, what is recent heavy rain showers?

RESHRA

In aviation weather, what is there if there is no significant change?

NOSIG

In Aviation, what is the four letter ICAO code for the airfield?

EGXX

In aviation weather, what is the date and time of observation indicated by?

141750Z

An increasing number of METAR reports are generated by automatic observing systems, without any human input or supervision. What are these METARS called?

Automatic METARS