Don't trust the TAF based on AUTO OBS

[checkremarks]

Nav Canada Doesn't even trust their own Auto OBS Machines either. They are faulty. I know that many are being replaced by one's that are more fancy. Also, remember folks that to use an alternate airport that has an aerodrome advisory forecast states:

Aerodromes served with an AERODROME ADVISORY forecast may qualify as
an alternate provided the forecast weather is no lower that 500 ft above the lowest
usable HAT/HAA and the visibility is not less than 3 miles

A.K.A VFR to use a place like Waterloo as an alternate even though they have fancy ILS and VOR approaches.

[photofly]

CYKF has a TAF, not an Advisory Forecast

[checkremarks]

CYKF has a TAF, not an Advisory Forecast

TAF CYKF 140138Z 1402/1404 22010KT P6SM BKN070 BKN120
RMK FCST BASED ON AUTO OBS. NXT FCST WILL BE ISSUED AT 140945Z=

I might be wrong but I thought a TAF based on AUTO OBS falls under "Aerodromes served with an AERODROME ADVISORY forecast may qualify as
an alternate provided the forecast weather is no lower that 500 ft above the lowest
usable HAT/HAA and the visibility is not less than 3 miles."

Yes it's a TAF but its a machine making it. The Machine can be completely wrong no? I've been using my theory on this for my IFR alternate planning for a while.

Photofly, I don't mean to down play your intelligence.

[photofly]

From TC AIM MET: (and I didn't know the details until I just looked it up)

1.3.4 Aerodrome Advisory Forecasts
Aerodrome advisories are forecasts that are issued in terminal
aerodrome forecast (TAF) format except that ‘ADVISORY’ is
added immediately after the period of coverage group. They are
issued in the place of a TAF when:

(a) Offsite: the forecast is based on observations that have been
taken offsite and are not considered to be representative of
weather conditions at the aerodrome;

(b) Observation Incomplete: the forecast is based on observations
which have regularly-missing or incomplete data; or

(c) No Specials: the forecast is based on observations from
a station with a limited observing program that does not
issue SPECI reports.

In each case, after the period of coverage group, the advisory
forecast will be labelled with the word “ADVISORY” and
the appropriate qualifier (OFFSITE, OBS INCOMPLETE, or
NO SPECI)



Nothing about automated observations.

[davecessna]

The one at CYSC was broken the last time I flew there. When I say one broken, every line in both the METAR and the TAF was reading broken sensor. Yay quebec.

[pelmet]

From TC AIM MET: (and I didn't know the details until I just looked it up)

1.3.4 Aerodrome Advisory Forecasts
Aerodrome advisories are forecasts that are issued in terminal
aerodrome forecast (TAF) format except that ‘ADVISORY’ is
added immediately after the period of coverage group. They are
issued in the place of a TAF when:

(a) Offsite: the forecast is based on observations that have been
taken offsite and are not considered to be representative of
weather conditions at the aerodrome;

(b) Observation Incomplete: the forecast is based on observations
which have regularly-missing or incomplete data; or

(c) No Specials: the forecast is based on observations from
a station with a limited observing program that does not
issue SPECI reports.

In each case, after the period of coverage group, the advisory
forecast will be labelled with the word “ADVISORY” and
the appropriate qualifier (OFFSITE, OBS INCOMPLETE, or
NO SPECI)



Nothing about automated observations.

The only place I have ever seen with this is Eureka way up at about 80 degrees north. The weather station is nearby but not at the airport. Usually nice weather there. Nice scenery too.