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Thequalifier VCwill be used to report certain significantweather phenomena
in the vicinity (between approximately 8 and 16 kmof the aerodrome
reference point) of the aerodrome.
Automatic PresentWeather Information
A report from anAWSwith a presentweather sensorwill includedata from
this sensor if the report is fully automated, inwhich case the abbreviation
AUTO is also included in themessage. Pilots shouldexercise cautionwhen
interpreting automated presentweather information, as itmay not be
equivalent to a human observation.
Cloud
Cloud height is given in hundreds of feet using three figures; e.g. 700 ft is
reported as 007.
Cloud amount is givenusing the following abbreviations listed on page124.
Cloud information is given from the lowest to thehighest layer ormass in
accordancewith the following:
• The lowest layer ormass, regardless of amount;
• The next layer ormass, coveringmore than2OKTAS;
• The next higher layer ormass, coveringmore than4OKTAS; and
• Cumulonimbus and/or towering cumulus cloudswhenever observed or
forecast andnot given in one of the groups above.
Typeof cloud is identified only for cumulonimbus and towering cumulus.
Thesewill be given asCB and TCU respectively.When an individual layer or
mass of cloud is composed of cumulonimbus and towering cumuluswith a
common cloud base, the typeof cloud is reported as cumulonimbus only, and
the amount shall be reported as the sum of theCB andTCU amounts.
Whenever cumulonimbus cloud is forecast, thedegreeof associated
thunderstorm activity or probability of occurrence is included.
A clear skywill be indicated in a report by SKC.When the sky is obscured,
the cloud group is omitted and vertical visibilitymay begiven in the format
VVhhh, where hhh is the vertical visibility in hundreds of feet.When
information on vertical visibility is not available, hhhmay be given as ///,
indicating that the sky is obscuredbut information on the vertical visibility is
not available.
2 – me t eorology
aerodrome forecasts and reports