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{{Merge|METAR}}
[[Image:3D_clouds.jpg|thumb|270px|[[3D clouds]] in [[PLIB]] version as seen from a [[EC135]].]]
[[Image:3D_clouds.jpg|thumb|270px|[[3D clouds]] in [[PLIB]] version as seen from a [[EC135]].]]
FlightGear has an impresive weather system, including real weather fetch, [[3D clouds]] and lightning.
FlightGear has an impresive weather system, including real weather fetch, [[3D clouds]] and lightning.


== METAR ==
==METAR==
{{Main article|METAR}}
[[Image:weather_scenario.jpg|thumb|250px]]
A [[METAR]] is a codified observation message indicating an airfield weather conditions observed at a given time. There are different ways of messaging weather reports, but in [[FlightGear]] is [[METAR]] used.


FlightGear is capable of receiving METAR weather data from real weather sources. It uses this information to determine elements of the flight environment, such as winds.
The [[METAR]]-message can be found acros the menu (Weather > Weather Scenario). To have the actual weather (or playing with [[ATC]]) you need to enable the Real weather fetch in the [[FlightGear Wizard]].


=== Reading a METAR Report ===
Such a message is established every hour.
Some tips on "speed reading" a METAR.


METAR KMKC 141754Z 31015G25KT 3SM -SHRA BR SCT020 BKN050 OVC100 22/17 A2991 RMK SLP128
===Explanation===
'''Example:'''
{| class="prettytable"; border="1" style="border-collapse:collapse; border:1px solid silver;"
|2008/03/15 12:24
|KSFO
|151224Z
|05012KT
|10SM
|SN
|BKN050
|02/M08
|A3016
|RMK AO2 SLP228
|T00221083
|-
|1
|2
|3
|4
|5
|6
|7
|8
|9
|10
|11
|}


The first set of numbers, followed by "Z" is the time of the report. After this is where the real meat of the METAR begins.
# Date
 
# [[ICAO]] Identifier (4-letter)
The first thing to look for is the wind report:
# Issuance Time DDHHMMz (UTC)
 
#*COR (CCD in Canada) if correction to observation
It is always a three digit Wind Heading in degrees (True) followed by Wind Speed.
#Wind
 
#*First 3 digits: True Wind direction or average if variable (VRB).
31015KT
#**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
reads:
#** KT=knots, KMH=kilometers/hour, MPS=meters/second
 
#*G (gust) as needed – 2 or 3 digit maximum speed
310* @ 15kts
#*Calm will be indicated by 00000KT
 
#*Example: 18012G22KT 150V240
or 310 degrees at 15 knots.
#Horizontal Visibility
 
#*Prevailing Visibility (PV)
Another important feature to look for is Wind Gust, if there are wind gusts the speed will appear after "G"
#**Statue miles (SM) and fractions (US & Canada only) or,
 
#**4 digit minimum visibility in meters, and,
31015G25KT
#**Lowest value and direction, as required (shown as a remark)
 
#*Runway Visual Range (RVR)
310* @ 15kts gusting to 25 kts
#**R: Runway Designator, L/R/C as needed, “/”
 
#**P/M: Plus/Minus (US only)
Visibility comes second after the Wind.
#**4 digit value (feet/meters)
 
#**V (variability) with tendency U/D/N (up/down/no change)
3SM
#**Example: R18R/1200FTV/U
 
#Present Weather (Constructed sequentially):
3 Statue Miles
#*Intensity
 
#*Descriptor
Visibllity is given in statute miles.
#*Precipitation (Dominant type is listed first if more than one type reported)
 
#*Obscuration
 
#*Other
Next, read the cloud cover or Sky Conditions report:
#Sky Cover
 
#*Cloud Description
SCT020 BKN050 OVC100
#**Amount in eights (octas)
 
#**SKC=Sky Clear (clear below 12,000 for ASOS/AWOS)
Scattered, Broken, Overcast.
#**NSC=No significant clouds
 
#**FEW=Few (1/8 to 2/8 sky cover)
The last but fairly important is the "Altimeter" or barometric pressure you should set your altimeter to.
#**SCT=Scattered (3/8 to 4/8 sky cover)
 
#**BKN=Broken (5/8 to 7/8 sky cover)
A2991
#**OVC=Overcast (8/8 sky cover)
 
#Terperature/Dewpoint (whole °C) (preceded by M=minus)
29.91 inches of mercury
#*First 2 digits = temperature
 
#*Second 2 digits = dewpoint
 
#Altimeter setting (QNH) and indicator (A=InHg, Q=hPa)
[http://www.alaska.faa.gov/fai/afss/metar%20taf/metcont.htm Metar Abbreviations]
#Supplementary Information
 
#*RE = Recent weather followed by weather codes
[http://www.alaska.faa.gov/fai/afss/metar%20taf/sametara.htm Reading METAR Reports]
#*WS = Windshear, followed by:
 
#**TKOF/LDG (takeoff/landing)
[http://www.wunderground.com/metarFAQ.asp Metar Tutorial]
#**RWY (2 digits runway identifier and designator L/R/C)
 
#*RMK = Remark
Technical: [http://search.cpan.org/~jzawodny/Geo-METAR-1.14/METAR.pm Decoding Metar in Perl]
#**SLP = Sea Level Pressure
 
#**T00221083 (Expanded temp/dewpoint)
(If I am wrong about anything, please correct).
#**1st, 5th digits: 0=plus, 1=minus
#**2nd-4th digits: temp (decimal missing) (02.2)
#**6th-8th digits: dewpoint (decimal missing) (-8.3)
#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 occurance 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 10Kilometers vis or greater)
#*Forecast Weather (as item 6)
#*Forecast Cloud (as item 7)


== TAF ==
== TAF ==

Revision as of 19:18, 25 March 2009

Merge-arrows.gif
It has been suggested that this article or section be merged with METAR.
3D clouds in PLIB version as seen from a EC135.

FlightGear has an impresive weather system, including real weather fetch, 3D clouds and lightning.

METAR

Weather scenario.jpg

A METAR is a codified observation message indicating an airfield weather conditions observed at a given time. There are different ways of messaging weather reports, but in FlightGear is METAR used.

The METAR-message can be found acros the menu (Weather > Weather Scenario). To have the actual weather (or playing with ATC) you need to enable the Real weather fetch in the FlightGear Wizard.

Such a message is established every hour.

Explanation

Example:

2008/03/15 12:24 KSFO 151224Z 05012KT 10SM SN BKN050 02/M08 A3016 RMK AO2 SLP228 T00221083
1 2 3 4 5 6 7 8 9 10 11
  1. Date
  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
  7. 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. Terperature/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 occurance 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 10Kilometers vis or greater)
    • Forecast Weather (as item 6)
    • Forecast Cloud (as item 7)

TAF

An Aerodrome Forecast (TAF) is a concise statement of the expected meteorological conditions at an airport during a specified period (usually 24 hours).

Reading TAF

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