METAR

src: i.ytimg.com

METAR is the format for reporting weather information. METAR weather reports are mostly used by pilots in fulfillment of part of pre-flight weather alerts, and by meteorologists, who use aggregate METAR information to assist in weather forecasts.

Raw METAR is the most common format in the world for transmitting observed weather data. It is highly standardized through the International Civil Aviation Organization (ICAO), which allows it to be understood in most parts of the world.

Video METAR

Naming

The Federal Aviation Administration (FAA) of the United States defines its Aviation Information Manual as its regular flight weather report while the international code-forming authority, WMO, holds the definition of the aerodrome routine meteorological report. The National Oceanic and Atmospheric Administration (part of the United States Department of Commerce) and the UK Meteoric Office both use the definitions used by the FAA. METAR is also known as the Route Meteorological Weather Map Routine or Aerodrome Meteorological Report.

Maps METAR

Origin

METAR usually comes from airports or permanent weather stations. Reports are generated once an hour or half hour, but if conditions change significantly, reports known as special (SPECI) may be issued. Some METARs are encoded by automatic airport airport stations located at airports, military bases, and other sites. Some locations still use additional observations, recorded by digital sensors, encoded through software, and then reviewed by certified weather observers or forecasters before being sent. Observations can also be made by skilled observers or forecasters who manually observe and encode their observations prior to transmission.

src: i.ytimg.com

History

The METAR format was introduced January 1, 1968 internationally and has been modified several times since then. North American countries continue to use the Aviation Surface Observation (SAO) for current weather conditions until June 1, 1996, when this report was replaced with a mutually agreed METAR variant agreed in the Geneva 1989 agreement. World Meteorological Organization (WMO) No. 782 "Aerodrome Reports and Forecasts" contains basic METAR codes as adopted by WMO member countries.

src: studentpilotnews.com

Information contained in METAR

METAR typically contains data for temperature, dew point, wind direction and velocity, precipitation, cloud cover and altitude, visibility, and barometer pressure. METAR may also contain information about the amount of deposition, lightning, and other information that would appeal to a pilot or meteorologist such as a pilot or PIREP report, color status and visual runway range (RVR).

In addition, short-term estimates called TREN may be added at the end of METAR which includes possible changes in weather conditions within two hours of observation. It's in the same format as the Aerodrome Terminal Forecast (TAF).

Complement METARs, reporting weather forecasts from the current weather, are TAFs. METAR and TAFs are used in VOLMET broadcasts.

src: i.ytimg.com

Rules

METAR codes are regulated by the World Meteorological Organization in consort with the International Civil Aviation Organization. In the United States, codes are granted authority (with some US national differences from the WMO/ICAO model) under Federal Meteorological Guidebook No. 1 (FMH-1), which paved the way for US Air Force Manual 15-111 on Surface Weather Observations, became official documents for the US Armed Forces. A form of code very similar to METAR is SPECI. Both codes are defined at the technical regulatory level in WMO Technical Regulation no. 49, Vol II, copied to WMO Manual No. 306 and to ICAO Annex III.

src: www.flyingineurope.be

METAR convention

Although the general format of METARs is a global standard, the specific field used in the format differs slightly between international usage and use generally in North America. Note that there may be minor differences between countries that use international code because there are between those who use the North American convention. Two examples illustrate the major differences between the two METAR variations.

src: i.ytimg.com

Example METAR code

International METAR Code

Here is an example of METAR from Burgas Airport in Burgas, Bulgaria. It was taken on 4 February 2005 at 16:00 Coordinated Universal Time (UTC).

METAR LBBG 041600Z 12012MPS 090V150 1400 R04/P1500N R22/P1500U SN BKN022 OVC050 M04/M07 Q1020 NOSIG 8849//91 =

• METAR indicates that the following is the standard hourly observation.
• LBBG is the ICAO airport code for Burgas Airport.
• 041600Z indicates the observation time. This is the day of the month (04) followed by the time of day (1600 Zulu time, which is equal to 4:00 pm Greenwich Mean time or 6:00 pm local time).
• 12012MPS shows wind direction from 120 Â ° (east-southeast) at a speed of 12 m/s (23 knots, 27 mph, 44 km/h). Measurement of speed can be in the knot (abbreviated KT) or meter per second (abbreviated MPS).
• 090V150 shows wind direction varying from 90 ° right (east) to 150 ° right (south-southeast).
• 1400 indicating the applicable visibility is 1,400 m (4,600Ã, ft).
• R04/P1500N shows Runway Visual Range (RVR) along runway 04 is 1,500 m (4,900Ã, ft) and has not changed significantly.
• R22/P1500U shows the RVR along runway 22 is 1,500 m (4,900Ã, ft) and rises.
• SN shows snow falling at a very high intensity. If rainfall starts with minus or plus (-/), it is light or heavy.
• BKN022 shows a damaged cloud layer (over half the sky) basically at 2,200 feet (670 m) above ground level (AGL). The lowest "BKN" or "OVC" layer determines the cloud ceiling.
• OVC050 shows an unbroken cloud layer (cloudy) basically at 5,000 ft (1,500 m) above ground level (AGL).
• M04/M07 shows the temperature -4 Â ° C (25 Â ° F) and dew point -7 Â ° C (19 Â ° F). The number M in front of the number indicates that the temperature/dew point is below zero Celsius.
• Q1020 shows the current altimeter setting (in QNH) is 1,020 hpa (30.12Ã, inHg).
• NOSIG is an example of TREND estimates added to METARs on the station while forecasters are being watched. NOSIG means that no significant changes are expected under reported conditions within the next 2 hours.
• 8849//91 indicates runway conditions:
  • 88 indicates a particular foundation (eg 25 = Rwy 25 or 25L; adding 50 will indicate Runway Right) or all airport runways ("88").
  • 99 indicates the last recurrence of the message as no new information is received.

Some locations will report runways using 3 characters (e.g. 25L)

• • 4 means runway lined with dry snow
  • 9 means 51% to 100% of the runway discussed
  • // means the thickness of the layer is not measurable or does not affect the use of the foundation
  • 91 means a bad braking index, in other words the tire has a bad grip on the runway
• CAVOK stands for C reduces A nd V OK , showing no clouds below 5,000 ft (1,500 m) or the highest minimum height of the sector and no cumulonimbus or cumulus looming at any level, visibility of 10 km (6 mi) or more and no significant weather changes.
• = indicates the end of METAR

North American METAR Code

METAR North America deviates from WMO (who wrote the code on behalf of ICAO) FM code 15-XII. The details are listed in the FAA's Aeronautical Information Manual (AIM), but non-conforming elements are largely based on the use of non-standard measurement units. This METAR example is from Trenton-Mercer Airport near Trenton, 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 =

• METAR indicates that the following is the standard hourly observation.
• KTTN is the ICAO identifier for Trenton-Mercer Airport.
• 051853Z indicates the day of the month is the 5th and the day time is 1853 Zulu/UTC, or 1:53 PM Eastern Standard Time.
• 04011KT shows winds from 040 ° right (northeast) at 11 knots (20 km/h, 13 mph). In the United States, the wind direction must have variations of 60 Â ° or greater for the variable wind direction to be reported and the wind speed should be greater than 3 knots (5.6 km/h; 3.5 mph).
• 1/2SM indicates the applicable visibility is ¹ / ₂ mi (800 m) SM = invite - invite miles.
• VCTS indicates a storm (TS) in the vicinity (VC), which means from 5-10 mi (8-16 km).
• SN shows snow falling at a moderate intensity; the previous plus or minus sign (/-) indicates heavy or mild rain. Unmarked/-, deposition is assumed.
• FZFG indicates the presence of frozen mist.
• BKN003 OVC010 shows broken ⁵ / ₈ to ^{7 / ₈} of the closed sky) at 300Ã, ft (91Ã, m) above ground level (AGL) and clouded layer (8/8 of the sky) at 1,000 Ã, ft (300 m).
• M02/M02 shows the temperature -2 Â ° C (28 Â ° F) and dew point -2 Â ° C (28 Â ° F). The letter M in front of the number indicates the temperature point/dew Celsius ("minus").
• A3006 shows the altimeter setting is 30.06 inHg (1.018Ã, hPa).
• RMK shows the following comment section.

Note that what follows is not part of standard observations outside the United States and may vary significantly.

• AO2 indicates that an automatic station with a discriminator precipitation sensor (rain/snow). Stations not equipped with rain/snow sensor set as AO1 .
• TSB40 shows the storm starting at 40 minutes past the clock at 1840 Zulu/UTC, or at 1:40. Eastern Standard Time.
• SLP176 shows the current barometric pressure extrapolated to the sea level is 1,017.6 hPa (30.05 inHg).
• P0002 indicates that 0.02 inches (0.5 Âμm) of the liquid equivalent precipitation accumulated during the last hour.
• T10171017 is the details of the temperature and dew point in eight digits separated into two groups of four. The first four digits (1017) show the temperature. The first digit (1) points above or below zero Celsius (0 = above zero 1 = below zero). The next three digits in the "017" group provide temperatures in degrees and one tenths of a degree Celsius, -1.7Ã,  ° C (28.9 Ã,  ° F). The last four digits "1017" show the dew point, -1,7Ã, ° C (28,9Ã, ° F). Note: The ASOS software, in this update, uses all degrees in Ã,  ° F to calculate the value of  ° C in this group.
• = indicates the end of METAR.

In Canada, RMK is followed by a description of cloud layer and opacity, in eight (octas). For example, CU5 will show the cumulus layer with ⁵ / ₈ opacity.

src: i.ytimg.com

Cloud reporting

Cloud coverage is reported by the number of 'octas' (eight) of the sky occupied by the cloud.

It is reported as:

src: i.ytimg.com

Airline categories in the US.

METAR can be expressed briefly using the so-called flight aviation category, which shows which flight classes can operate at each airport with reference to the visibility and the ceiling of each METAR. Four categories are used in the US:

src: aviadordeprofesion.files.wordpress.com

METAR WX code

METAR abbreviation is used in the WX section. The description section will also include the start and end times of the weather event.

The code before the comment will be listed as "-RA" for "light rain". The code listed after the comment can be listed as "RAB15E25" for "The rain starts at 15 minutes after the top of the last hour and ends at 25 minutes after the top of the last hour."

src: www.flyingineurope.be

US. METAR stands for

The following METAR abbreviations are used in the United States; some are used worldwide:

METAR and TAF Abbreviations and Acronyms:

src: i.ytimg.com

AS. METAR numeric code

Additional METAR numeric codes are registered after RMK.

src: us.123rf.com

WMO code for cloud type

The following code identifies the cloud type used in section 8/nnn.

src: www.researchgate.net

See also

• BUFR
• CLIMAT
• IWXXM
• Surface weather observations
• SYNOP
• TAF
• Forecast types of trends

src: previews.123rf.com

References

External links

Decoding

• METAR Study Guide - approved by the Canadian National Weather Service Director of the Environment
• Wunderground METAR Tutorial
• FlightUtilities.com METAR and TAF online decoder
• METARreader.com online decoder
• metarchecker.com translates metar report

Format specifications

• OFCM.gov - The Federal Meteorological Handbook A. No. 1 - Surface Weather Observations and Reports (September 2005). Complete documentation on METAR format, PDF.
• metar.NOAA.govÃ, - Information about METAR and TAF reports. Also provides links to METAR and current cycle files.
• WMO documentation about the METAR format

Software library

• Perl Module for parsing METAR reports on CPAN sites
• PhpWeather is a PHP application (with GNU General Public License) that parses METAR reports.
• pymetar and metarÃ, - Python libraries for METAR retrieve and parse

Current report

• Selection of worldwide METAR reports from the U.S. NOAA
• List of stations in the NOAA database. Use CTRL F to search for stations. Enter a four-letter ICAO identifier to METAR Worldwide Data Access from the U.S. NOAA.
• CheckWXÃ, - METAR Raw and translated, METAR cycles, trends, and graphs for locations around the world.
• How to create a METAR/TAF browser bookmark for airport groups - An easy method to check the worldwide METAR/TAF weather reports right now from your browser.

Current reports and history

• Wunderground.comÃ, - searchable by location, can view historical METARs by location.

Wind roses based on METAR data

• Wind roses for 2011
• Wind roses for 2012
• wind roses for 2013
• roses for 2014
• roses for 2015

Source of the article : Wikipedia