Aviation – weather forecasting..

While writing my thoughts on Learning to Fly, it did occur to me that this is more of a new world than I’d ever really anticipated, possibly naively.

Anyway, that’s not a moan, just an observation – but there are some things that persist in that world despite the world moving on.

Take the world of weather forecasting for example. Here we encounter TAF’s and METAR’s – basically a string of numbers and acronyms to give a pretty accurate local forecast. Now I believe the reason for all the codes used was that it allows a lot of information to be passed in a short time.

METAR – current local observation

TAF – 24 hour local forecast

But in the world of t’internet, smart phones, tablets etc, that need for brevity seems somewhat less compelling, at least from my armchair..

TAF 190457Z 1906/2006 30009KT CAVOK BECMG 1921/1924 24010KT BECMG 2000/2003 BKN040 PROB30 TEMPO 2002/2006 7000 -RA

This one was issued on 19th Nov at 04:57 GMT – it actually doesn’t say the month – they’re updated at least twice a day, so no need. It was for Edinburgh Airport, if that matters..

1906/2006 30009KT CAVOK : valid between 06:00 on 19th and 06:00 on 20th, wind 9 knots from 300o , visibility unlimited (10 Km or more), no significant weather or cloud

BECMG 1921/1924 24010KT : Becoming, between 21:00 and midnight on 19th, wind 10 knots from 240o

BECMG 2000/2003 BKN040 : Becoming, between 00:00 hrs and 03:00 on 20th, no change in wind, broken clouds at 4,000 ft

PROB30 TEMPO 2002/2006 7000 -RA : 30% probability, that temporarily between 02:00 and 06:00 on 20th, visibility 7000 metres, light rain

So to read a TAF it helps to first download the codex for it – aka. “Get Met”


Having got that, the met office offers yet another explanation of the arcane art of decoding a TAF https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/services/transport/aviation/ga/what-taf-values-really-mean.pdf

Fun, eh?

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