CYYC Metar question

[freakonature]

The remarks section of the 1900z metar for YYC makes mention of contrails. I have never seen this before. Is it that they are obscuring the sky significantlly to mention it?

[matrix]

I've seen this many times before. I always thought it was more for climatology / forecasting purposes.

http://www.wrh.noaa.gov/fgz/science/con ... hp?wfo=fgz

On days where the contrails disappear quickly or don't even form, they can expect continuing good weather, while on days where they persist, a change in the weather pattern may be expected.

[mike53]

Just a guess but for a contrail to form you must have moisture .We have all witnessed high flying jets that produce no contrails ergo no moisture present.To me it would be a heads-up to possible future weather expectations.?

[MrWings]

It is a heads up to wear your gas mask at altitude as chem spraying is in progess. At least that's what they told us at Skull and Bones Aviation College.

[W0XOF]

COTRA (contrails, water vapour and the presence of condensation nuclei, both from the jet engine exhaust) is reported in the RMK section of the METAR which indicates instability in the upper levels. This remark is included for the forecasters.