3. Reading aerodrome forecasts

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A Terminal Aerodrome Forecast (or TAF for short) is a concise coded statement of the expected meteorological conditions at an airport during a specified period of time. TAFs are used in aviation to accurately and unambiguously transmit updates about wind, visibility, significant weather phenomena (such as, for instance, dust storms), cloud coverage, air temperature, etc. This information is useful in drone surveying as well, as it helps to determine whether it’s the right time to fly to collect high-quality imagery. 

The TAF in Australia consists of the following information:

  • Message identification (i.e., TAF)
  • Location identifier
  • Time of origin (in Coordinated Universal Time or UTC)
  • Validity period
  • Forecast surface wind
  • Forecast visibility
  • Forecast significant weather
  • Forecast cloud amount and height
  • Forecast significant changes and variations
  • Possibility of poor visibility
  • Statement of turbulence
  • Forecast temperatures and atmospheric pressure (also known as QNH)


An example of TAF would look something like that:


TAF AMD YSBK 241854Z 2420/2508 VRB03KT CAVOK
FM242300 02010KT SCT040 BKN100 PROB30 2420/2423 2000 MIST
INTER 2506/2508 7000 LIGHT SHOWERS OF RAIN BKN020
T 17 21 19 15 Q 1016 1014 1013 1013


We’ll now break it down and look at each code separately.

TAF means that this is a Terminal Area Forecast.

AMD means that the TAF has been amended since its initial issue time.

YSBK is the location of the aerodrome that produced this forecast (in this case, the code stands for Bankstown aerodrome).

241854Z is the TAF issue date and time. The first two digits represent the day of the month, which in this case is the 24th. The next four digits stand for the time, which here is 18:54. Don’t forget, the times are shown in UTC, so you’ll need to convert them to the time zone where the aerodrome is located (for Bankstown that is Australian Eastern Daylight Time or AEDT).

2420/2508 represents the validity period for the transmitted forecast. In this example the validity is from the 24th day 20:00 UTC to the 25th day 08:00 UTC.

VRB03KT is decoded as the wind from variable direction at 3 knots.

CAVOK means clouds and visibility OK.  This code is used when visibility is greater than 10 km, there are no clouds below 5000 ft, no cumulonimbus, no precipitation, thunderstorms, shallow fog, low drifting snow, or dust devils.

FM242300 02010KT 9999 mean that from 23:00 on the 24th the wind will change speed and direction. Wind direction from True North will be 020 degrees (identified as 20 degrees True), which means that the wind direction will be north-north-east and its speed will change to 10 knots. 9999 indicates that visibility will be 10 kilometres or more.

SCT040 BKN100 codes (along with many others) represent the cloud amount and height above the aerodrome (in 100's of feet). SCT and BKN specifically stand for scattered and broken. 

PROB30 2420/2423 2000 MIST mean that between 20:00 and 23:00 UTC on the 24th there is a 30% probability of the visibility dropping to 2000 m in mist.

INTER 2506/2508 7000 LIGHT SHOWERS OF RAIN BKN020 indicate that rain showers are due from 06:00 UTC on the 25th until the end of the forecast. For periods of up to 30 minutes (signified by INTER or intermittent) the visibility is expected to reduce to 7000 m and the cloud lowering to 5-7 OKTAS at 2000 ft. 

T 17 21 19 15 Q 1016 1014 1013 1013 represent the temperature and QNH in 3 hourly intervals from the start of the forecast period. In this case, at 20:00 the temperature is predicted to be 17 degrees C and QNH - 1016 hPa.


Let’s now have an attempt at reading the aerodrome forecast for the Murramarang National Park area where the project is taking place.

Reading aerodrome forecasts check-point

Your task is to check and decode the forecast of Moruya airport, which is the closest to Murramarang National Park. To complete this check-point, go through the following steps:

  1. Go into the forecast database and search for Moruya airport using its location code YMRY. 
  2. Copy and paste your forecast to a blank document on your computer
  3. Decode your forecast using these resources:
    http://www.bom.gov.au/aviation/data/education/taf.pdf
    ,
    http://www.bom.gov.au/aviation/knowledge-centre/,
    https://uni.edu/storm/Wind%20Direction%20slide.pdf 
  4. Save your complete forecast report for reference later.


Reading forecasts is important, but you also need to pay attention to the weather conditions on the ground, so that’s what we are moving onto right now!