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What is a METAR?
- An hourly scheduled observation of:
- Type
- Station
- Time
- Wind
- Visibility
- RVR
- Weather
- Sky condition
- Temp/dew point
- Altimeter setting
- Remarks
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Winds:
- Reported in true degrees
- 25015KT: 250° at 15 knots
- 25015G30KT: 250° at 15 knots gusting 30
- 0000KT: calm winds
- 25015G30KT 210V290: wind varying between 210° and 290°
- VRB03KT: wind variable at or less than 6 knots
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Visibility:
- Greatest visibility observed over 50% of the horizon
- If less than 7SM, then weather/obstruction to vision will be reported
- M1/4SM: less than 1/4 SM visibility
- VIS 1V2: visibility variable between 1 and 2 miles; in remarks section
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Runway visual range (RVR):
- Reported when visibility ≤ 1SM or RVR≤6000
- ≤ 3000': reported in 300' increments
- ≥ 3000': reported in 500: increments
- R32L/1000FT: runway 32L is 1000'
- M0600FT: RVR ≤ 600'
- P6000FT: RVR ≥ 6000'
- R06R2000V4000FT: RVR 6R, variable between 2000' and 4000' between the two thresholds
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Weather:
- Weather in the body is within 5 miles from station
- VC indicates weather 5-10 miles from the station
- Weather occurring beyond 10 miles is in the remarks section
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Weather: Description
BC, BL, DR, FZ, MI, PR, SH, TS
- BC: Patches
- BL: Blowing
- DR: Low drifting
- FZ: Freezing
- MI: Shallow
- PR: Partial
- SH: Shower(s)
- TS: Thunderstorm
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Weather: Precipitation
DZ, GR, GS, IC, PL, RA, SG, SN, UP
- DZ: drizzle
- GR: hail, diam. ≥ .25"
- GS: small hail < .25"
- IC: Ice crystals
- PL: Ice pellets
- RA: rain
- SG: snow grains
- SN: snow
- UP: unknown precipitation (automated only)
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Weather: Obstruction
BR, DU, FG, FU, HZ, PY, SA, VA
- BR: mist, vis ≥ 5/8SM
- DU: widespread dust
- FG: fog, vis ≥ 5/8SM
- FU: smoke
- HZ: haze
- PY: spray
- SA: sand
- VA: volcanic ash
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Weather: other
DS, FC, PO, SQ, SS
- DS: dust storm
- FC: funnel cloud(s)
- PO: well developed dust/sand storm
- SQ: squalls
- SS: sandstorm
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Sky condition:
- Layers reported in ascending order up to the first overcast
- Reported in AGL
- To constitute a ceiling, coverage must be greater than 4/8 (broken)
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Sky condition:
SKC or CLR, FEW, SCT, BKN, OVC, VV
- SKC or CLR: sky clear below 12,000'
- FEW: Few, 0-2/8; ≤ 1/8 reported as FEW
- SCT: scattered, 3/8-4/8
- BKN: broken, 5/8-7/8, constitutes ceiling
- OVC: overcast, 8/8, constitutes ceiling
- VV: vertical visibility; VV002 = 200'
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Temperature and dew point:
- 19/18: temp- 19C; dew point 18C
- 01/M01: Temp- 1C; dew point -1C
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Altimeter:
A2992: 29.92 inHg
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Remarks:
RMK
- Manual or automated
- Plain language
- additive data and maintenance
- SLP: sea level pressure; place a 10 or 9 before first digit, and decimal before last digit.
- Use 9 only if 3 digit value is >500
- SLP034: sea level pressure 1003.4 millibars
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Runway condition:
WR, SLR, LSR, PSR, IR, RCRNR
- WR: wet runway
- SLR: slush on runway
- LSR: loose snow on runway
- PSR: packed snow on runway
- IR: ice on runway
- RCRNR: not reported
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Runway condition reading:
- 2 digit reading
- "//" indicates runway is wet, slush-covered, or reading is unavailable
- 02-05: NIL; Increase landing roll +100%
- 06-12: POOR; increase landing roll 99-46%
- 13-18: FAIR; increase landing roll 45-16%
- 19-25: GOOD; Increase landing roll 15-9%
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How long are TAF forecast good for?
Typically 24hrs but can be up to 30 hrs
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TAF: date and time
- 6 digit
- 260909: 26th day; 0900Z to 0900Z the next day
- Civil stations 091720Z 091818: transmission time 9th day, at 1720; forecast 9th day from 1800Z to 1800Z the next day
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TAF: wind
- measured in degrees true
- If expected to vary by 60° or more, it will be noted at WND 270V350 in the remarks section
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TAF: visibility
- If the visibility is ≤ 6SM, the weather or obstruction to vision will be included
- 9999: indicates greater than 7SM
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TAF: icing
- comes after sky coverage
- 6 digit code
- First digit is always 6
- Second digit is type- most severe reported
- Next 3 digits indicate base of icing band
- Last digit is the thickness of icing in 1000s'
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TAF: turbulence
- 6 digit code
- First digit is always 5
- Second digit is intensity
- Next 3 digits is base of turbulence
- Last is thickness of turbulence layer
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TAF: altimeter
- Lowest expected altimeter setting in inHg
- QNH: sea level pressure
- INS: unit of measure, inches
- QNE: standard datum plane, 29.92 inHg
- QFE: station pressure, not corrected to sea level
- Civil stations do not forecast altimeter setting
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TAF: change groups
FM, BECMG, TEMPO
- FM: from, change is expected to be quick
- BECMG: change is expected to occur over longer period of time
- TEMPO: temporary, non-permanent change
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What are the differences between civilian and military TAFs?
- Civil stations will use statute miles instead of meters
- Civil stations include date time group of transmission prior to the forecast period
- When military stations amend, correct, or have a routine delayed forecast, a remark will be appended to the last line of the forecast with the appropriate time
- Civil stations may include probability of precipitation occurence
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