So some of you asked me to play the weather girl 👯♀️ … and finally explain that cryptic #airport #weather stuff!
Of course we‘re in #aviation – which means worldwide understandable standards are key.
The „Queen Mom“ of regulations once again is @icao. Their recommendations on meteorology are contained in Annex III: who reports what, when, and how.
There‘s 3 types of #aerodrome text weather.
- METAR (meteorological aerodrome report): routine report of actual conditions, issued every 30/60 mins
- SPECI (specific met report): similar to METAR, but issued in case of rapid changes in between normal intervals
- TAF (terminal aerodrome forecast): forecasts normally covering 24-30h periods, issued every 6h
Each of these 3 has a distinct structure, grouping info in fix sequence so a METAR will look the same worldwide.
Additionally, instead of plain language, universal coding is used to keep things short, easy to transmit and standardized.
All of that makes things super handy once one has learned the basics.
So let‘s have a look at the latest METAR OF UUDD (Moscow-Domodedovo;).
- aerodrome‘s 4 letter ICAO code; SA prefixes an “actual“ report.
- observation time. Day of the month plus time in UTC here, 03rd 0300Z.
- surface wind. First 3 digits for wind direction in degrees true, to be read as „wind from 100 deg“ (so, from the east). Last 2 for speed (in knots or m/s, depending on region), here 2 MPS.
- visibility in meters (here, 8000m) – with lowes VIS OF 1000m when looking towards east (my inner weather nerd mumbles something about „sunrise going on in the east).
- significant weather phenomena – as a 2-letter abbreviation. Eg. BR = mist.
- clouds. First, amount in Octas, with FEW=1-2, SCT(scattered)=3-4, BKN(broken)=5-7, OVC(overcast)=8; then cloud base height in 100ft…or NSC for “no significant cloud“. 3 octas in 2000ft height eg are SCT020.
- temperature/dew point, both in degrees celsius.
- QNH, aka atmospheric pressure adjusted for sea level.
- Runway state group
- trend for +2h (200m visibility in fog)
For TAF, TEMPOrary / long-term changes („bec(o)m(in)g“) complement the same basic „wording“.
Can you de-code the TAF from the image top-right?