Joined: 11 Dec 2005
|Posted: Wed Sep 04, 2013 11:06 am Post subject: Automated METAR Observations
|Automated METAR Observations
Some caution needs to be taken when interpreting automated visibility, weather and cloud information as they may not be equivalent to human observations.
An example of an automated METAR observations is as under:
METAR YSCN 052230Z AUTO 27016KT 9999NDV // BKN025 15/05 Q0997 RMK RF00.2/04.6 METAR
METAR: A routine observation when conditions are at or above specified levels. In cases of low cloud, visibility or strong winds the observation will be identified as a SPECI.
YSCN: The location of the observation (Camden).
052230Z: The origination date/time of the METAR which is given in UTC using a six figure group followed by the abbreviation Z ("Zulu").
AUTO: METAR only contains automated observations.
27016KT: Wind direction in degrees true and speed in knots.
9999NDV: The visibility reported in meters. 9999 means visibility greater than 10km. NDV means "No Directional Variation".
|These groups only appear in METAR AUTO, i.e. fully automated messages. The NDV group is appended to the visibility meter value to indicate that, as we have only one visibility meter per site, there is No Directional Variation reporting capability (as there is with manual reports). |
//: Element not available from an automated observation. In this instance Weather (e.g RA - Rain) is not available.
|e.g. METAR YPKS 060000Z AUTO 20009KT //// // ////// 12/06 Q1024 RMK RF00.0/000.0
In this example, three elements (Visibility, Weather, Cloud) are not available.
BKN025: Amount of cloud reported in hundreds of feet. Broken cloud (5-7 OKTAS) at 2,500ft AGL.
NCD: If NCD is indicated it means "no cloud detected".
15/05: Temperature and dew point.
Q0997: QNH given as a four figure number.
RMK: Remarks. In this example they include Rainfall (RF) recorded in the 10 minutes prior to the observation in millimeters (0.2mm), and the rainfall recorded since 0900 local time (4.6mm).