METAR & TAFs

 

Meteorological Aerodrome Report (METAR)

Terminal Aerodrome Forecasts (TAF)
METARs & TAF decoder

Meteorological Aerodrome Report (METAR)
A METAR is an observation of current surface weather reported in a standard international format. METARs are issued on a regularly scheduled basis unless significant weather changes have occurred.

METARs typically come from airports or permanent weather observation stations. Reports are generated once an hour or half-hour, but if conditions change significantly (such as rapidly changing weather conditions, aircraft mishaps, or other critical information), a report known as a special (SPECI) may be issued.

*Tempo forecast & Becoming forecast

Tempo - Less the an hour at a time
Becoming - supersedes initial forecast

Terminal Aerodrome Forecasts (TAF)
A TAF is a report established for the five statute mile radius around an airport. TAF reports are usually given for larger airports. Each TAF is valid for a 24 or 30-hour time period and is updated four times a day at 0000Z, 0600Z, 1200Z, and 1800Z. The TAF utilizes the same descriptors and abbreviations as used in the METAR report.

Decoding a METAR & TAF is you’re bread and butter and something you will have to do for every single flight, making sure the weather is suitable and the weather Minima for you’re flight is acceptable is you’re responsibility as acting pilot in command and should be conducted as part of you’re pre flight planning.

The METAR in our example is broken down into 8 informative segments: but usually you can get up to 12 information segments to a Standard METAR - here is a summary of the available information from your typical METAR:-

1. Type of report—there are two types of METAR reports. The first is the routine METAR report that is transmitted on a regular time interval. The second is the aviation selected SPECI. This is a special report that can be given at any time to update the METAR for rapidly changing weather conditions, aircraft mishaps, or other critical information.

2. Station identifier— EGHH, Bournemouth International Airport , four-letter code as established by the International Civil Aviation Organization (ICAO)

3. Date (day) and time of report—27/0420Z Zulu depicted in a six-digit group (270420Z). The first two digits are the date. The last four digits are the time of the METAR/SPECI, which is always given in Coordinated Universal Time (UTC). A “Z” is appended to the end of the time to denote the time is given in Zulu

4. Wind— 210° @ 07 Kt (27007KT) reported with five digits (04009KT) unless the speed is greater than 99 knots, in which case the wind is reported with six digits. The first three digits indicate the direction the true wind is blowing from in tens of degrees. If the wind is variable, it is reported as “VRB.” The last two digits indicate the speed of the wind in knots unless the wind is greater than 99 knots, in which case it is indicated by three digits. If the winds are gusting, the letter “G” follows the wind speed (G26KT). After the letter “G,” the peak gust recorded is provided. If the wind direction varies more than 60° and the wind speed is greater than six knots, a separate group of numbers, separated by a “V,” will indicate the extremes of the wind directions. 00000KT = calm. Wind direction is given in degrees true.

5. Visibility— 6000m- (meters) the prevailing visibility (10 SM) is reported in statute miles as denoted by the letters “SM.” It is reported in both miles and fractions of miles. At times, runway visual range (RVR) is reported following the prevailing visibility. RVR is the distance a pilot can see down the runway in a moving aircraft. When RVR is reported, it is shown with an R, then the runway number followed by a slant, then the visual range in feet. For example, when the RVR is reported as R17L/1400FT, it translates to a visual range of 1,400 feet on runway 17 left. *0000 = 'less than 50 metres' 9999 = 'ten kilometres or more'. No direction is required.

6. Weather—+ = Heavy (well developed in the case of +FC and +PO); - = Light;
no qualifier = Moderate.
BC=Patches DS=Duststorm
FG=Fog GS=Small hail or snow pellets
PL=Ice pellets SA=Sand SQ=Squalls VA=Volcanic ash BL=Blowing DU=Dust FU=Smoke HZ=Haze PO=Dust devils SH=Showers SS=Sandstorm VC=In vicinity
BR=Mist DZ=Drizzle FZ=Freezing
IC=Ice crystals PR=Banks SG=Snow grains TS=Thunderstorm DR=Drifting FC=Funnel cloud GR=Hail (>5mm) MI=Shallow
RA=Rain SN=Snow UP=Unidentified

7. Sky condition—FEW='few' (1-2 oktas), SCT='Scattered' (3-4 oktas), BKN='Broken' (5-7 oktas),OVC='Overcast' Cloud amounts are measured in oktas - one okta = one eighth of cloud cover.
always reported in the sequence of amount, height, and type or indefinite ceiling/height (vertical visibility) (BKN008 OVC012CB, VV003). The heights of the cloud bases are reported with a three-digit number in hundreds of feet AGL. Clouds above 12,000 feet are not detected or reported by an automated station. The types of clouds, specifically towering cumulus (TCU) or cumulonimbus (CB) clouds, are reported with their height. Contractions are used to describe the amount of cloud coverage and obscuring phenomena. The amount of sky coverage is reported in eighths of the sky from horizon to horizon.

8. Temperature and dew point——the air temperature and dew point are always given in degrees Celsius (C) or (18/17). Temperatures below 0 °C are preceded by the letter “M” to indicate minus. If dew point is missing, example would be reported as 18///

9. Altimeter setting—Q1008  Q indicates the sea level pressure hectopascals. If the letter A is used QNH is in inches and hundredths.  reported as inches of mercury ("Hg) in a four-digit number group (A2970). It is always preceded by the letter “A.”

10. Zulu time—a term used in aviation for UTC, which places the entire world on one time standard.

11. Remarks—— the remarks sectional ways begins with the letters “RMK.” Comments may or may not appear in this section of the METAR. The information contained in this section may include wind data, variable visibility, beginning and ending times of particular phenomenon, pressure information, and various other information deemed necessary. An example of a remark regarding weather phenomenon that does not fit in any other category would be: OCNL LTGICCG. This translates as occasional lightning in the clouds and from cloud to ground. Automated stations also use the remarks section to indicate the equipment needs maintenance.