Decodeer METAR & TAF

Een METAR is een gecodeerd observatiebericht dat de weersomstandigheden op een vliegveld aangeeft die op een bepaald moment zijn waargenomen. Zo’n bericht wordt elk uur opgesteld.
Een SPECI-bericht is identiek aan een METAR, maar wordt punctueel opgesteld in plaats van regelmatig. Het is een speciale observatieboodschap die elke belangrijke verandering sinds de laatste METAR of SPECI aangeeft.
Een TAF is een terminalprognose. Het wordt om de paar uur uitgegeven en wordt, indien nodig, eerder bijgewerkt.

Aviation Routine Weather Report (METAR)

Voorbeeld:

METARKRNO210056Z05012KT10SM-SNBKN05002/M08A3016RMK AO2 SLP228T00221083
1234567891011

1 Message Type
-METAR: routine weather report
-SPECI: special weather report, triggered by a weather change
-AUTO will be first item for ASOS/AWOS generated reports

2 ICAO Identifier (4-letter)

3 Issuance Time DDHHMMz (UTC)
– COR (CCD in Canada) if correction to observation

4 Wind
-First 3 digits: True Wind direction or average if variable (VRB).
Note: If the wind direction varies 60° or more, the direction will be indicated with a V (e.g. 180V250)
-Next 2 digits: Mean speed and units
-KT=knots, KMH=kilometers/hour, MPS=meters/second
-G (gust) as needed – 2 or 3 digit maximum speed
-Calm will be indicated by 00000KT
-Example: 18012G22KT 150V240

5 Horizontal Visibility
-Prevailing Visibility (PV)
-Statue miles (SM) and fractions (US & Canada only) or,
-4 digit minimum visibility in meters, and,
-Lowest value and direction, as required (shown as a remark)
-Runway Visual Range (RVR)
-R: Runway Designator, L/R/C as needed, “/”
-P/M: Plus/Minus (US only)
-4 digit value (feet/meters)
-V (variability) with tendency U/D/N (up/down/no change)
-Example: R18R/1200FTV/U

6 Present Weather (Constructed sequentially):
-Intensity
-Descriptor
-Precipitation (Dominant type is listed first if more than one type reported)
-Obscuration
-Other
-Sky Cover
-Cloud Description
-Amount in eights (octas)
SKC=Sky Clear (clear below 12,000 for ASOS/AWOS)
NSC=No significant clouds
FEW=Few (1/8 to 2/8 sky cover)
SCT=Scattered (3/8 to 4/8 sky cover)
BKN=Broken (5/8 to 7/8 sky cover)
OVC=Overcast (8/8 sky cover)

8 Temperature/Dewpoint (whole °C) (preceded by M=minus)
-First 2 digits = temperature
-Second 2 digits = dewpoint

9 Altimeter setting (QNH) and indicator (A=InHg, Q=hPa)

10 Supplementary Information
-RE = Recent weather followed by weather codes
-WS = Windshear, followed by:
-TKOF/LDG (takeoff/landing)
-RWY (2 digits runway identifier and designator L/R/C)
-RMK = Remark
-SLP = Sea Level Pressure
-T00221083 (Expanded temp/dewpoint)
–1st, 5th digits: 0=plus, 1=minus
–2nd-4th digits: temp (decimal missing) (02.2)
–6th-8th digits: dewpoint (decimal missing) (-8.3)

11 Trend Forecast (2 hours from time of observation) (Not used in US)
-PROB and 2 digits (30 or 40) = probability 30% or 40%
-Used to indicate the probability of occurrence of alternate element(s) or temporary fluctuations
-Change Indicator
-BECMG = Becoming (used where changes are expected to reach or pass through specified values
-TEMPO = Temporary (fluctuations of less than one hour duration
-NOSIG = No significant change
-Forecast Wind (same as item 4)
-Forecast Visibility (as item 5) (9999 indicates 10 Kilometers vis or greater)
-Forecast Weather (as item 6)
-Forecast Cloud (as item 7)

QualifierWeather Phenomena
DescriptorPrecipitationObscurationOther 
BCPatchesDZDrizzleBRMist (1)DSDuststorm 
BLBlowing (2)GRHail (3)DUWidespread Dust 
DRLow Drifting (4)GSSmall Hail and/or snow pellets (5)FGFog (6)FCFunnel Clouds 
FZFreezingICIce CrystalsFUSmokePODust/Sand Whirls 
MIShallowPLIce PelletsHZHazeSQSquall(s) 
PRPartialRARainSASand 
SHShower(s)SGSnow GrainsVAVolcanic AshSSSandstorm 

(1)    Visibility at least 1000m (5/8SM) but not more than 9600m (6SM)
(2)    6 feet or more above the ground
(3)    Hailstone diameter 5mm or greater
(4)    Less than 6 feet above the ground
(5)    Hailstone diameter less than 5mm
(6)    Visibility less than 1000m (5/8SM)
(7)    Within 8 KM(5SM) of the aerodrome but not at the aerodrome