TAF availability and advisory forecasts
TAF availability: not every aerodrome has one.
- Only aerodromes with a regular, complete METAR and SPECI observation program meeting Transport Canada standards.
- Observations must represent the aerodrome (not a site far from the field).
- TAF covers weather within roughly 5 NM of the aerodrome.
TAF service hours:
| Aerodrome | Service |
|---|---|
| International airports | 24-hr mandatory (only here) |
| Other TAF aerodromes | May run 24-hr, 30-hr, or seasonal 24-hr |
- TAF Locations chart can be incomplete or out of date; confirm TAF status via current flight publications and NOTAM.
Aerodrome advisory forecast: issued by the forecast office instead of a TAF when the aerodrome can't sustain the TAF observation program.
- TAF format, with
ADVISORYright after the period-of-validity group, plus a qualifier giving the reason:
| Qualifier | Meaning |
|---|---|
OFFSITE |
Observations away from aerodrome centre, not representative |
OBS INCOMPLETE |
Observations regularly have missing or incomplete data |
NO SPECI |
Limited observing program, no SPECIs issued |
Trap: assuming every aerodrome has a TAF; trusting the TAF Locations chart over flight publications and NOTAM; reading an advisory forecast as a full TAF (substitutes for one, on a weaker observation base); confusing observation representativeness with the roughly 5 NM area a TAF describes.
References
- TC AIM MET 1.3.3
- TC AIM MET 1.3.4
- TC AIM MET 7.1
- TC AIM MET 7.2