METARis a format for reportingweatherinformation. A METAR weather report is predominantly used byaircraft pilots,and bymeteorologists,who use aggregated METAR information to assist inweather forecasting.
Raw METAR is the most common format in the world for the transmission of observational weather data.[citation needed]It is highly standardized through theInternational Civil Aviation Organization(ICAO), which enables it to be understood throughout most of the world.
Report names
editIn its publication theAeronautical Information Manual(AIM), the United StatesFederal Aviation Administration(FAA) describes the report asaviation routine weather report,[1]while the international authority for the code form, theWorld Meteorological Organization(WMO), describes it as theaerodrome routine meteorological report.TheNational Oceanic and Atmospheric Administration(part of theUnited States Department of Commerce) and the United Kingdom'sMet Officeboth employ the definition used by the FAA. METAR is also known asMeteorological Terminal Aviation Routine Weather Report[2]orMeteorological Aerodrome Report.[3]
Frequencies and types
editMETARs typically come fromairportsor other permanentweather observation stations.Reports are generated once an hour or half-hour at most stations, but if conditions change significantly at a staffed location, a report known as a special (SPECI) may be issued.[4]: 2 [note 1]Some stations make regular reports more frequently, such asPierce County Airport(ICAO code: KPLU) which issues reports three times per hour.[5]In addition to METARs and SPECIs, ASOS One-Minute Observations (OMO) are updated once a minute. OMOs can be in various formats, including the METAR format.[4]: 3
Some METARs are encoded byautomated airport weather stationslocated at airports, military bases, and other sites. Some locations still use augmented observations, which are recorded by digital sensors, encoded via software, and then reviewed by certified weather observers or forecasters prior to being transmitted. Observations may also be taken by trained observers or forecasters who manually observe and encode their observations prior to transmission. In the United States, prior to mid-1990s, most observations are made manually, but today the vast majority are automated or augmented observations.[4]: 2
History
editThe METAR format was introduced internationally on 1 January 1968, and has been modified a number of times since.North Americancountries continued to use a Surface Aviation Observation (SAO) for current weather conditions until 1 June 1996, when this report was replaced with an approved variant of the METAR agreed upon in a 1989Genevaagreement. The WMO's publication No. 782 "Aerodrome Reports and Forecasts" contains the base METAR code as adopted by the WMO member countries.[6]
Information contained in a METAR
editA typical METAR contains data for the airport identifier, time of observation,winddirection and speed,visibility,current weather phenomena such asprecipitation,cloudcover and heights,temperature,dew point,andbarometric pressure.This information forms the body of the report, consisting a maximum of 11 groups of information.[4]: 5 A METAR may also contain information on precipitation amounts,lightning,and other information that would be of interest to pilots or meteorologists such as apilot reportor PIREP,colour statesandrunway visual range(RVR). These may be provided in coded or plain language and appended to the end of the METAR as remarks.[4]: 6
In addition, a short period forecast called aTRENDmay be added at the end of the METAR covering likely changes in weather conditions in the two hours following the observation. These are in the same format as aTerminal Aerodrome Forecast(TAF).
The complement to METARs, reporting forecast weather rather than current weather, are TAFs. METARs and TAFs are used inVOLMETbroadcasts.
Cloud reporting
editCloud coverageis reported by the number of "oktas"(eighths) of the sky that is occupied by cloud. Automated substation substitutes time averaging of sensor data gathered during 30-minute period prior to reporting.[4]: 2, 4
This is reported as:[7]
| Abbreviation | Meaning |
|---|---|
| SKC | "No cloud/Sky clear" used worldwide but in North America is used to indicate a human generated report[8][9] |
| NCD | "Nil Cloud detected" automated METAR station has not detected any cloud, either due to a lack of it, or due to an error in the sensors |
| CLR | "No clouds below 12,000 ft (3,700 m) (US) or 25,000 ft (7,600 m) (Canada)", used mainly within North America and indicates a station that is at least partly automated[8][9] |
| NSC | "No (nil) significant cloud",i.e.,none below 5,000 ft (1,500 m) and noTCUorCB.Not used in North America. |
| FEW | "Few" = 1–2 oktas |
| SCT | "Scattered" = 3–4 oktas |
| BKN | "Broken" = 5–7 oktas |
| OVC | "Overcast"= 8 oktas,i.e.,full cloud coverage |
| TCU | Towering cumulus cloud,e.g.,SCT016TCU |
| CB | Cumulonimbus cloud,e.g.,FEW015CB |
| VV | "Vertical visibility" = clouds cannot be seen because of fog or heavy precipitation, so vertical visibility is given instead. |
The following codes identify thecloud typesused in the 8/nnn part of RMK.[10]
| Code | Low clouds | Middle clouds | High clouds |
|---|---|---|---|
| 0 | none | none | none |
| 1 | Cumulus (fair weather) |
Altostratus (thin) |
Cirrus (filaments) |
| 2 | Cumulus (towering) |
Altostratus (thick) |
Cirrus (dense) |
| 3 | Cumulonimbus (no anvil) |
Altocumulus (thin) |
Cirrus (often withcumulonimbus) |
| 4 | Stratocumulus (fromcumulus) |
Altocumulus (patchy) |
Cirrus (thickening) |
| 5 | Stratocumulus (notcumulus) |
Altocumulus (thickening) |
Cirrus/cirrostratus (low in sky) |
| 6 | StratusorFractostratus (fair) |
Altocumulus (fromcumulus) |
Cirrus/cirrostratus (hi in sky) |
| 7 | Fractocumulus/fractostratus (bad weather) |
Altocumulus (withaltocumulus, altostratus,nimbostratus) |
Cirrostratus (entire sky) |
| 8 | Cumulusandstratocumulus | Altocumulus (with turrets) |
Cirrostratus (partial) |
| 9 | Cumulonimbus (thunderstorm) |
Altocumulus (chaotic) |
Cirrocumulusor Cirrocumulus/cirrus/cirrostratus |
| / | not valid | above overcast | above overcast |
Wind reporting
editWind observation measures the horizontal vector component of the wind, which includes both direction and speed. These are determined by evaluating the measurement over a 2-minute period.[4]: 24–10
The wind direction is coded with the first three digits in tens of degrees relative to thetrue north.If wind speed is less than or equal to 6 kn (11 km/h; 6.9 mph), the wind direction will be displayed as variable or "VRB". If the wind speed is greater than 6 knots, but the direction varies more than 60° in the past 2 minutes, METAR will report the range of wind direction. For example,21010KT 180V240suggests the wind was variable from 180° to 240° at 10 knots.[4]: 10
Immediately after the wind direction is the wind speed, coded in two or three digits measured in knots, km/h or m/s. If during past 10 minutes, the weather station detects more than 10 kn (19 km/h; 12 mph) between minimum and maximum windspeed, METAR determines awind gustexists and reports the maximum instantaneous windspeed.[4]: 10
If the air is motionless, the wind will be reported as calm and coded as00000KT.[4]: 10
Visibility and runway visual range
editVisibility measures the atmospheric opacity. It is the greatest distance where at least half of the horizon circle can be seen from the surface.[4]: 11
Runway visual range(RVR) is an instrument-derived measurement that suggests the horizontal distance an observer may see down the runway. In the US, for stations with RVR reporting capacity, this information is omitted from the METAR unless the visibility is at or below 1 mi (1.6 km), or the designated instrument runway's RVR is at or below 6,000 ft (1,800 m). RVR of up to four designated runways may be reported, depending on the country.[4]: 11
Regulations and conventions
editMETAR code is regulated by theWorld Meteorological Organizationin consort with the International Civil Aviation Organization. In the United States, the code is given authority (with some US national differences from the WMO/ICAO model) under theFederal Meteorological Handbook No. 1(FMH-1), which paved the way for theUS Air ForceManual 15-111[11]on Surface Weather Observations, being the authoritative document for the US Armed Forces. A very similar code form to the METAR is the SPECI. Both codes are defined at the technical regulation level in WMO Technical Regulation No. 49, Vol II, which is copied over to the WMO Manual No. 306 and to ICAO Annex III.
Although the general format of METARs is a global standard, the specific fields used within that format vary somewhat between general international usage and usage within North America. Note that there may be minor differences between countries using the international codes as there are between those using the North American conventions — ICAO allows member countries to modify METAR code for use in their particular countries, as long as ICAO is notified.[4]: 5
Examples
editThe two examples which follow illustrate the primary differences between the international and the North American METAR variations.[10][12][page needed]
International METAR codes
editThe following is an example METAR fromBurgas AirportinBurgas,Bulgaria.It was taken on 4 February 2005 at 16:00Coordinated Universal Time(UTC).
METAR LBBG 041600Z 12012MPS 090V150 1400 R04/P1500N R22/P1500U +SN BKN022 OVC050 M04/M07 Q1020 NOSIG 8849//91=
- METARindicates that the following is a standard hourly observation.
- LBBGis theICAO airport codeforBurgas Airport.
- 041600Zindicates the time of the observation. It is the day of the month (04) followed by the time of day (1600Zulu time,which equals 4:00 pmGreenwich Mean Timeor 6:00 pm local time).
- 12012MPSindicates thewind directionis from 120° (east-southeast) at a speed of 12m/s(23knots;27 mph; 44 km/h). Speed measurements can be in knots (abbreviated KT) or metres per second (abbreviated MPS).
- 090V150indicates the wind direction is varying from 90° true (east) to 150° true (south-southeast).
- 1400indicates theprevailing visibilityis 1,400 m (4,600 ft).
- R04/P1500Nindicates the Runway Visual Range (RVR) alongrunway04 is 1,500 m (4,900 ft) and not changing significantly.
- R22/P1500Uindicates RVR along runway 22 is 1,500 m (4,900 ft) and rising.
- +SNindicatessnowis falling at a heavy intensity. If any precipitation begins with a minus or plus (-/+), it's either light or heavy.
- BKN022indicates a broken (over half the sky) cloud layer with its base at 2,200 ft (670 m)above ground level(AGL). The lowest "BKN" or "OVC" layer specifies thecloud ceiling.
- OVC050indicates an unbroken cloud layer (overcast) with its base at 5,000 ft (1,500 m) above ground level (AGL).
- M04/M07indicates the temperature is −4 °C (25 °F) and thedew pointis −7 °C (19 °F). An M in front of the number indicates that the temperature/dew point isbelow zeroCelsius.
- Q1020indicates the currentaltimeter setting(inQNH) is 1,020hPa(30.12inHg).
- NOSIGis an example of aTRENDforecast which is appended to METARs at stations while a forecaster is on watch. NOSIG means that no significant change is expected to the reported conditions within the next 2 hours.
- 8849//91indicates the condition of the runway.
- The first two characters indicate which runway is being described.
- If there are two or more runways with the same number, some locations will use three characters (e.g.25Land25R). Otherwise, the left runway will use just its number and the right runway will add 50 (e.g.25= 25L and75= 25R).
- 88indicates all the airport's runways.
- 99indicates repetition of the last message as no new information received.
- 4means the runway is coated with dry snow
- 9means 51% to 100% of the runway is covered
- //means the thickness of the coating was either not measurable or not affecting usage of the runway
- 91means the braking index is bad, in other words the tires have bad grip on the runway
- The first two characters indicate which runway is being described.
- CAVOKis an abbreviation forCeilingAndVisibilityOK,indicating no cloud below 5,000 ft (1,500 m) or the highest minimum sector altitude and nocumulonimbusortowering cumulusat any level, a visibility of 10 km (6 mi) or more and no significant weather change.[13]
- =indicates the end of the METAR
North American METAR codes
editNorth American METARs deviate from the WMO (who write the code on behalf of ICAO) FM 15-XII code. Details are listed in the FAA'sAeronautical Information Manual(AIM), but the non-compliant elements are mostly based on the use of non-standard units of measurement. This METAR example is fromTrenton-Mercer AirportnearTrenton,New Jersey,and was taken on 5 December 2003 at 18:53 UTC.
METAR KTTN 051853Z 04011KT 1/2SM VCTS SN FZFG BKN003 OVC010 M02/M02 A3006 RMK AO2 TSB40 SLP176 P0002 T10171017=[14]
- METARindicates that the following is a standard hourly observation.
- KTTNis the ICAO identifier for theTrenton-Mercer Airport.
- 051853Zindicates the day of the month is the 5th and the time of day is 1853 Zulu/UTC,or 1:53PMEastern Standard Time.
- 04011KTindicates the wind is from 040° true (north east) at 11 knots (20 km/h; 13 mph). In the United States, the wind direction must have a 60° or greater variance for variable wind direction to be reported and the wind speed must be greater than 3 knots (5.6 km/h; 3.5 mph).
- 1/2SMindicates the prevailing visibility is1⁄2mi (800 m) SM = statutemile.
- VCTSindicates athunderstorm(TS) in the vicinity (VC), which means from 5–10 mi (8–16 km).
- SNindicates snow is falling at a moderate intensity; a preceding plus or minus sign (+/-) indicates heavy or light precipitation. Without a +/- sign, moderate precipitation is assumed.
- FZFGindicates the presence of freezingfog.
- BKN003 OVC010indicates a broken (5⁄8to7⁄8of the sky covered) cloud layer at 300 ft (91 m)above ground level(AGL) and an overcast (8/8 of the sky covered) layer at 1,000 ft (300 m).
- M02/M02indicates the temperature is −2 °C (28 °F) and the dew point is −2 °C (28 °F). An M in front of the number indicates a negative Celsius temperature/dew point ( "minus" ).
- A3006indicates the altimeter setting is 30.06 inHg (1,018 hPa).
- RMKindicates the remarks section follows.
Note that what follows are not part of standard observations outside of the United States and can vary significantly.
- AO2indicates that the station is automated with a precipitation discriminator (rain/snow) sensor.[note 2]Stations that aren't equipped with a rain/snow sensor are designatedAO1.[15]
- TSB40indicates the thunderstorm began at 40 minutes past the hour at 1840 Zulu/UTC,or 1:40 p.m.Eastern Standard Time.
- SLP176indicates the current barometric pressure extrapolated to sea level is 1,017.6 hPa (30.05 inHg).
- P0002indicates that 0.02 inches (0.5 mm) ofliquid-equivalent precipitation accumulated during the last hour.
- T10171017is a breakdown of the temperature and dew point in eight digits separated into two groups of four. The first four digits (1017) indicate the temperature. The first digit (1) designates above or below zero Celsius (0=above zero 1=below zero). The next three digits in the group "017" give the temperature in degrees and tenths of a degree Celsius, −1.7 °C (28.9 °F). The last four digits "1017" indicate the dew point, −1.7 °C (28.9 °F). Note: ASOS software, as of this update, uses whole degrees in °F to compute the °C values in this group.[citation needed]
- =indicates the end of the METAR.
In Canada,RMKis followed by a description of the cloud layers and opacities, in eighths (oktas). For example, CU5 would indicate a cumulus layer with5⁄8opacity.[16]
Flight categories in the US
editMETARs can be expressed concisely using so-calledaviation flight categories,which indicates what classes of flight can operate at each airport by referring to the visibility and ceiling in each METAR. Four categories are used in the US:[17]
| Category | Visibility | Ceiling |
|---|---|---|
| VFR | > 5 mi | and > 3000 ft AGL |
| Marginal VFR | Between 3 and 5 mi | and/or between 1,000 and 3,000 ft AGL |
| IFR | 1 mi or more but less than 3 mi | and/or 500 ft or more but less than 1,000 ft |
| Low IFR | < 1 mi | and/or < 500 ft |
METAR weather codes
editMETAR abbreviations used in the weather and events section. Remarks section will also include begin and end times of the weather events.[10]Codes before remarks will be listed as "-RA" for "light rain". Codes listed after remarks may be listed as "RAB15E25" for "Rain began at 15 minutes after the top of the last hour and ended at 25 minutes after the top of the last hour."
Combinations of two precipitation types are accepted;e.g.,RASN (rain and snow mixed), SHGSSNetc.If more than one type of weather is present, METAR will report in the following order:[4]: 13
- Tornadic activity
- Thunderstorm
- Most dominating weather
- Precipitation
- Obscuration
| Type | Abbr. | Meaning |
|---|---|---|
| Intensity | - | Light intensity |
| Intensity | (blank) | Moderate intensity |
| Intensity | + | Heavy intensity |
| Descriptor | VC | In the vicinity (5–10mi/ 8–16kmfromstation); visible phenomena: TS, SH, FG, DS, SS, VA, PO, FC, BLSN, BLDU, BLSA |
| Descriptor | RE | Recent hour's most important past phenomenon with residues: TS, RA, FZRA, SN, BLSN, GR, GS, PL (e.g.:METAR... Q1010 RERA=) |
| Descriptor | MI | Shallow[French:Mince](fog descriptor) |
| Descriptor | PR | Partial (fog descriptor) |
| Descriptor | BC | Patches[French:Bancs](fog descriptor) |
| Descriptor | DR | Low drifting below eye level; including:DRSN,DRSA, DRDU |
| Descriptor | BL | Blowing at or above eye level; including:BLSN,BLSA, BLDU |
| Descriptor* | SH | Showers(*also without precipitation: VCSH) |
| Descriptor* | TS | Thunderstorm(*also without precipitation: VCTS, RETS or asthunder) |
| Descriptor | FZ | Freezing; including:FZDZ,FZRA,FZFG |
| Precipitation | DZ | Drizzle |
| Precipitation | RA | Rain |
| Precipitation | SN | Snow(snowflakes) |
| Precipitation | SG | Snow grains |
| Precipitation | GS | Graupel[French:Grésil],snow pellets and/or small hail (not in the US).[note 3][18]Elsewhere hail is GR when it is 5 mm or greater[19]Outside of the US when the hail is less than 5 mm the code GS is used.[19]) |
| Precipitation | GR | Hail[French:Grêle](in the US includes small hail)[note 3] |
| Precipitation | PL | Ice pellets |
| Precipitation | IC | Ice crystals |
| Precipitation | UP | Unknown precipitation |
| Obscuration | FG | Fog(visibilityless than 1 km) |
| Obscuration | BR | Mist[French:Brume](due to water droplets, visibility between 1 and 5 km)[note 4] |
| Obscuration | HZ | Haze(due to dry particulates, visibility between 1 and 5 km)[note 4][4]: 3 |
| Obscuration | VA | Volcanic ash |
| Obscuration | DU | Widespread dust |
| Obscuration | FU | Smoke[French:Fumée] |
| Obscuration | SA | Sand |
| Obscuration | PY | Spray, only coded as BLPY |
| Other | SQ | Squall |
| Other | PO | Dust[French:Poussière]orsand whirls |
| Other | DS | Duststorm |
| Other | SS | Sandstorm |
| Other | FC | Funnel cloud |
| Time | B | Began at time |
| Time | E | Ended at time |
| Time | 2 digits | Minutes of current hour |
| Time | 4 digits | Hour/minutes Zulu time |
US METAR abbreviations
editThe following METAR abbreviations are used in the United States; some are used worldwide:[10]
METAR and TAF abbreviations and acronyms:
| Abbreviation | Meaning | Abbreviation | Meaning |
|---|---|---|---|
| $ | maintenance check indicator | / | indicator that visual range data follows; separator between temperature and dew point data. |
| ACC | altocumulus castellanus | ACFT MSHP | aircraft mishap |
| ACSL | altocumulus standinglenticular cloud | ALP | airport location point |
| ALQDS | all quadrants (official) | ALQS | all quadrants (unofficial) |
| AO1 | automated station without precipitation discriminator | AO2 | automated station with precipitation discriminator |
| APCH | approach | APRNT | apparent |
| APRX | approximately | ATCT | airport trafficcontrol tower |
| AUTO | fully automated report | C | center (with reference to runway designation) |
| CA | cloud-airlightning | CB | cumulonimbus cloud |
| CBMAM | cumulonimbusmammatus cloud | CC | cloud-cloud lightning |
| CCSL | cirrocumulusstandinglenticular cloud | cd | candela |
| CG | cloud-ground lightning | CHI | cloud-height indicator |
| CHINO | sky condition at secondary location not available | CIG | ceiling |
| CONS | continuous | COR | correction to a previously disseminated observation |
| DOC | Department of Commerce | DOD | Department of Defense |
| DOT | Department of Transportation | DSIPTG | dissipating |
| DSNT | distant | DVR | dispatch visual range |
| E | east, ended, estimated ceiling (SAO) | FAA | Federal Aviation Administration |
| FIBI | filed but impracticable to transmit | FIRST | first observation after a break in coverage at manual station |
| FMH-1 | Federal Meteorological Handbook No.1, Surface Weather Observations & Reports (METAR) | FMH2 | Federal Meteorological Handbook No.2, Surface Synoptic Codes |
| FROPA | frontalpassage | FROIN | frost on the indicator |
| FRQ | frequent | FT | feet |
| FZRANO | freezing rain sensor not available | G | gust |
| HLSTO | hailstone | ICAO | International Civil Aviation Organization |
| INCRG | increasing | INTMT | intermittent |
| KT | knots | L | left (with reference to runway designation) |
| LAST | last observation before a break in coverage at a manual station | LST | local standard time |
| LTG | lightning | LWR | lower |
| M | minus, less than | MAX | maximum |
| METAR | routine weather report provided at fixed intervals | MIN | minimum |
| MOV | moved/moving/movement | MT | mountains |
| N | north | N/A | not applicable |
| NCDC | National Climatic Data Center | NE | northeast |
| NOS | National Ocean Service | NOSPECI | no SPECI reports are taken at the station |
| NOTAM | Notice to Airmen | NW | northwest |
| NWS | National Weather Service | OCNL | occasional |
| OFCM | Office of the Federal Coordinator for Meteorology | OHD | overhead |
| OVR | over | P | indicates greater than the highest reportable value |
| PCPN | precipitation | PK WND | peak wind |
| PNO | precipitation amount not available | PRES | pressure |
| PRESFR | pressurefalling rapidly | PRESRR | pressurerising rapidly |
| PWINO | precipitation identifier sensor not available | R | right (with reference to runway designation),runway |
| RTD | Routine Delayed (late) observation | RV | reportable value |
| RVR | Runway visual range | RVRNO | RVRsystem values not available |
| RWY | runway | S | south |
| SCSL | stratocumulusstandinglenticular cloud | SE | southeast |
| SFC | surface,i.e.,ground level) | SLP | sea-level pressure |
| SLPNO | sea-level pressurenot available | SM | statute miles |
| SNINCR | snow increasing rapidly | SOG | snow on the ground |
| SPECI | an unscheduled report taken when certain criteria have been met | STN | station |
| SW | southwest | TCU | towering cumulus |
| TS | thunderstorm | TSNO | thunderstorminformation not available |
| TWR | tower | UNKN | unknown |
| UTC | Coordinated Universal Time | V | variable |
| VIS | visibility | VISNO | visibility at secondary location not available |
| VR | visual range | VRB | variable |
| W | west | WG/SO | Working Group for Surface Observations |
| WMO | World Meteorological Organization | WND | wind |
| WS | wind shear | WSHFT | wind shift |
| Z | Zulu,i.e.,Coordinated Universal Time |
US METAR numeric codes
editAdditional METAR numeric codes listed after RMK.[10]
| Code | Description |
|---|---|
| 11234 | 6-hour maximum temperature. Follows RMK with five digits starting with 1. Second digit is 0 for positive and 1 for negative. The last 3 digits equal the temperature in tenths.
This example value equals −23.4 °C (−10 °F). |
| 20123 | 6-hour minimum temperature. Follows RMK with five digits starting with 2. Second digit is 0 for positive and 1 for negative. The last 3 digits equal the temperature in tenths.
This example value equals 12.3 °C (54 °F). |
| 4/012 | Total snow depth in inches. Follows RMK starting with 4/ and followed by 3 digit number that equals snow depth in inches.
This example value equals 12 inches of snow currently on the ground. |
| 402340123 | 24-hour maximum and minimum temperature. Follows RMK with nine digits starting with 4. The second and sixth digit equals 0 for positive for 1 for negative. Digits 3–5 equal the maximum temperature in tenths and the digits 7–9 equals the minimum temperature in tenths.
This example value equals 23.4 °C (74 °F) and 12.3 °C (54 °F). |
| 52006 | 3-hour pressure tendency. Follows RMK with 5 digits starting with 5. The second digit gives the tendency. In general 0–3 is rising, 4 is steady and 5–8 is falling. The last 3 digits give the pressure change in tenths of a millibar in the last 3 hours.
This example indicates a rising tendency of 0.6 millibars (0.018 inHg).[20] |
| 60123 | 3- or 6-hour precipitation amount. Follows RMK with 5 digits starting with 6. The last 4 digits are the inches of rain in hundredths. If used for the observation nearest to 00:00, 06:00, 12:00, or 18:00 UTC, it represents a 6-hour precipitation amount. If used in the observation nearest to 03:00, 09:00, 15:00 or 21:00 UTC, it represents a 3-hour precipitation amount.
This example shows 1.23 inches (31 mm) of rain. |
| 70246 | 24-hour precipitation amount. Follows RMK with 5 digits starting with 7. The last 4 digits are the inches of rain in hundredths.
This example shows 2.46 inches (62 mm) of rain. |
| 8/765 | Cloud cover using WMO code. Follows RMK starting with 8/ followed by a 3 digit number representing WMO cloud codes. |
| 98060 | Duration of sunshine in minutes. Follows RMK with 5 digits starting with 98. The last 3 digits are the total minutes of sunshine.
This example indicates 60 minutes of sunshine. |
| 931222 | Snowfall in the last 6 hours. Follows RMK with 6 digits starting with 931. The last 3 digits are the total snowfall in inches and tenths.
This example indicates 22.2 inches (560 mm) of snowfall. |
| 933021 | Liquid water equivalent of the snow (SWE). Follows RMK with 6 digits starting with 933. The last 3 digits are the total inches in tenths.
This example indicates 2.1 inches (53 mm) SWE. |
See also
editNotes
edit- ^Criteria for issuing a SPECI includes beginning or ending of hazardous weather, aircraft mishap, decreasing visibility or ceiling, or any other condition deemed critical by the observer of the responsible agency.[1]
- ^Precipitation discriminators are electrically heated at sub-freezing temperatures to calculate the water equivalent of frozen precipitation and snow accumulation.
- ^abIn the US small hail is included with regular hail and the Remarks section is used saying "GR LESS THAN 1/4".
- ^abIf the difference between temperature and dewpoint is less than or equal to 2°C, the station reports the condition as haze; else mist is reported.
References
edit- ^ab"Chapter 7. Safety of Flight. Section 1. Meteorology".Aeronautical Information Manual.Federal Aviation Administration.Archivedfrom the original on 2009-09-05.Retrieved2024-12-27.
- ^METAR (MEteorological Terminal Aviation Routine Weather Report) Station Networkat the Centre for Environmental Data Archival
- ^Aerodrome Meteorological Observation and Forecast Study Group (AMOFSG)at ICAO.
- ^abcdefghijklmno"Chapter 24: Observations".Aviation Weather Handbook(FAA-H-8083-28A ed.).Federal Aviation Administration.2024.
- ^"Pierce County-Thun Field".National Weather Service.NOAA.Retrieved27 December2024.
- ^"782 – Aerodrome reports and forecasts: A user's handbook to the codes".World Meteorological Organization.Retrieved2009-09-23.
- ^"Aerodrome Weather Report – World Meteorological Organization"(PDF).Archived fromthe original(PDF)on 2012-02-24.
- ^abSky Condition Group NsNsNshshshs or VVhshshs or SKCDepartment of Atmospheric Sciences at Texas A&M University
- ^ab"MET – 3.0 Appendices".Archived fromthe originalon October 31, 2011.
- ^abcde"METAR/TAF List of Abbreviations and Acronyms"(PDF).National Weather Service.
- ^"Air Force Manual 15-111"(PDF).Archived fromthe original(PDF)on May 27, 2011.
- ^Pilot's Handbook of Aeronautical Knowledge(FAA-H-8083-25C ed.).Federal Aviation Administration.2023-07-17.
- ^Get Met 2012Archived2012-05-18 at theWayback Machinepublished by the UK Met Office, p 13
- ^Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR)
- ^Key to METAR Surface Weather Observations
- ^"METAR Study Guide".MétéoCentre.com.Retrieved28 March2012.
- ^"Aeronautical Information Manual, Section 7-1-7, 'Categorical Outlooks'".Federal Aviation Administration.Archived fromthe originalon 2012-07-26.
- ^"METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR)"(PDF).
- ^ab10.2 Section II – hourly observations "UTC".See 10.2.10 Column 32 – weather and obstructions to vision.
- ^"Metar Help".College of DuPage.
External links
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- Decoding
- Format specifications
- OFCM.gov— US Federal Meteorological Handbook No. 1 — Surface Weather Observations and Reports (September 2005). Complete documentation on the METAR format, PDF.
- Software libraries
- Perl modules for parsing METAR reportsat theCPANsite
- PhpWeatheris aPHPapplication (with aGNU General Public License) that parses METAR reports.
- pymetarandmetar—Pythonlibraries for METAR fetching and parsing
- Using METAR data to see the Atmospheric Tide
- Current reports
- Selection of worldwide METAR reports from the US NOAA
- List of Stations in NOAA database.Use CTRL+F to search for a station. Input four-letter ICAO identifier toWorldwide METAR Data Access from the US NOAA.
- CheckWX— Raw and decoded METARs, METAR cycles, trends and graphs for locations worldwide