TAF translation for a newbie....
:confused:
for Leeds Bradford (EGNM) today LEEDS BRADFORD EGNM 061516Z 061601 15010KT 9999 SCT020 TEMPO 1620 7000 SHRA BKN010TCU PROB30 TEMPO 1620 4000 +SHRA +TSRA BKN008CB BECMG 1720 24006KT BECMG 2023 7000 BKN008 TEMPO 2301 3000 BR BKN003 Can someone explain it please. It has been explained once before to me but not in writing so I can refer back to it and get used to reading them. I understand bits but not other parts. Thanks in advance Liam. |
If you register free at Met Office: Weather and climate change then log on and go to Met Office: Online services - customer login you will find the answer
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Well done G-EMMA that looks pretty good to me!
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or
Egnm 061516z 061601 Crap Wx
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In short, it means you ain't goin' anywhere! :(
Greatest TAF decode I've heard so far: If the TAF is: 1 line - you can pretty well go 2 lines - Only people with IMC ratings are going anywhere 3 lines - no one's goin' anywhere As crude as it sounds, it's not often that far off! :) |
... and times are given in UTC.
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Well done G-EMMA. Just one minor addition. Every "BECMG" and "TEMPO" group supersedes the previous, and in most cases the PROB groups will be aligned with the timing of the BECMG and TEMPO groups so they also supersede the previous.
So if you want to break it down into multiple paragraphs, here's how to do that: EGNM 061516Z 061601 15010KT 9999 SCT020 <- The general overall picture at the start of the period, so at 16Z. Anything in here that's not superseded later on will remain valid throughout the period. TEMPO 1620 7000 SHRA BKN010TCU <- Temporary condition between 16Z and 20Z, after which, if nothing else mentioned, it reverts back to 15010KT 9999 SCT020 PROB30 TEMPO 1620 4000 +SHRA +TSRA BKN008CB <- But within this same period it might get worse. BECMG 1720 24006KT <- Ah, between 17Z and 20Z the wind will become 240/6. But for the rest the previous still applies. So theoretically, if the forecast holds true, at 20Z the conditions are 24006KT 9999 SCT020 BECMG 2023 7000 BKN008 <- And this is what's going to get established from 20Z to 23Z. So at 23Z the conditions should be 24006KT 7000 BKN008. TEMPO 2301 3000 BR BKN003 <- And from 23Z onwards it will worsen once again. Oh, and all times are UTC, not local. |
Pretty cool Text: EGNM 061810Z 061904 24006KT 9999 SCT020 Forecast period: 1900 to 2000 UTC 06 July 2008 Where does the 2000 UTC comes from? This bit applies to 0400 UTC, doesn't it? Oh no, later on, you'll find BECMG 2023 7000 BKN008 So that's where the 2000 UTC comes from. So... Pretty smart analysis algorithm, lousy presentation of the results. This is the site I like better: MET'MAP - ORBIFLY FLIGHT SCHOOL - IFR ET CPL AMERICAIN EN EUROPE - FAA IFR AND CPL IN EUROPE Mouse over a site to see the METAR and its interpretation. Click on a site to make it your personal center of the universe, then bookmark whatever URL is listed for next time. They don't interpret TAFs though, only METARS. But they do give access to both the short and long term TAFs and I also like the color coding to get a glance of flight conditions. Especially if you combine that with rainfall radar or something like that. |
I was taught that the longer the TAF, the worse it is to fly...! ;)
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Well, I just got proper training so that I could read and understand them the same way I read and understand a book. Oh, and proper training in meteorology, climatology, forecasting, modelling, and so forth too.
How little I knew, eh? |
If the TAF is: 1 line - you can pretty well go 2 lines - Only people with IMC ratings are going anywhere 3 lines - no one's goin' anywhere |
Been looking at that ADDS thing a bit more. There's something seriously wrong with that algorithm. The interpretation is done correctly, as is the presentation. But then the wrong bits of TAF are associated with the presentation bits. Everything is well (excellent, actually) up to the PROB30 bit.
Then comes the following line: Text: PROB30 And some text suggesting it interprets that line. But what that piece of text actually interprets is Text: PROB30 TEMPO 1920 4000 +SHRA +TSRA BKN008CB which is correct, as this is one "block". The next "block" then seems to interpret the line Text: BECMG 2023 7000 BKN008 But this line is listed after the block it interprets. Because the line preceding it is the "TEMPO 1920 ..." line which should have been on the PROB30 line. So past the PROB30 bit, all the content of the "Text:" lines need to be shifted up one block to make things fit. And even then the interpretation block doesn't neatly interprets what's on the "Text:" line, since the interpretation also looks through the rest of the TAF for anything that precedes or supersedes this bit of "Text:" line. Just guessing what happened: A smart programmer wrote an algorithm to make a linear interpretation of a TAF, from hour to hour, and present it in text form. Which worked flawlessly. And this is no mean feat, because to interpret what the weather is going to be at the end of the period may mean going backwards in the TAF a few "blocks", and to interpret how long the initial weather is going to last may mean going forward in the TAF. Then a customer request comes along to have the actual TAF text inbetween the interpretation. Which isn't possible in this case since a TAF isn't necessary linear, but the algorithm linearizes the results. So the smart programmer refuses, tries to explain this to his non-understanding management or non-understanding customers, and moves on. Anyway, request persists, so a less intelligent programmer comes along, willing to take the job (after all, a TAF is in ALL CAPS so it can't be difficult), finds he doesn't understand the code programmer #1 has written so he writes his own algoritm that breaks the TAF into blocks. And then injects these blocks into the blocks that the original algorithm spews out. A quick test by management finds no flaws with this so the thing goes into production. And the worst thing is that that second programmer probably made a lot of money. First for taking on a job that everybody said was impossible, and secondly for getting it through acceptance testing. In less time than expected. (Is it true you turn into a cynic after working in the same field for 10 years?:*) |
30% chance that temporarily between 4 in the afternoon and 8 in the evening it will deteriate to visibility of 4000m in heavy showers of rains and heavy thunderstorms and rain, cloud lowering to broken at 800ft cumulonimbus For anyone who may not be too familiar with the geography of the UK, Hebden and Brimham Rocks are places in the Yorkshire Dales National Park. :) |
wx is always crap at LBA :}
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...
most accurate forecast I've heard recently...
The Weather is PANTs........Poor Actuals and Naff TAFs |
Been looking at that ADDS thing a bit more. There's something seriously wrong with that algorithm. The interpretation is done correctly, as is the presentation. But then the wrong bits of TAF are associated with the presentation bits. Everything is well (excellent, actually) up to the PROB30 bit. avbrief=# select count(*) from taf where icao ~~ 'K%' and text ~ 'PROB30'; count ------- 349 (1 row) avbrief=# select count(*) from taf where icao ~~ 'K%' and text ~ 'PROB30 TEMPO'; count ------- 0 (1 row) avbrief=# select count(*) from taf where icao ~~ 'EG%' and text ~ 'PROB30'; count ------- 205 (1 row) avbrief=# select count(*) from taf where icao ~~ 'EG%' and text ~ 'PROB30 TEMPO'; count ------- 200 (1 row) Looking at some of the examples, TEMPO seems to be implied by PROB30 in some cases. Thus my guess is that the algorithm was not tested on cases where two change words like "PROB30 TEMPO" appear consecutively. |
Come to think of it, I like the US system better. I mean PROB30 would imply a TEMPO condition, wouldn't it? In what sort of situations would you have a PROB30 BECMG?
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Come to think of it, I like the US system better. I mean PROB30 would imply a TEMPO condition, wouldn't it? In the first case, the airport might well be fogged out for the entire period. In the second case, there should be an opportunity to make an approach at some stage. Don't bet your life on it though. |
Thanks for all the replies and discussion.
Great thing t'nternet aint it :) |
dont you just hate PROB50 +SHRA
it might rain it might not ..... I can do that type of forecast for free... |
There's a big difference between "3000 BKN006 PROB30 0710 0200 FG OVC000" and "3000 BKN006 PROB30 TEMPO 0710 0200 FG OVC000". We've put the question at several AeroExpos and other exhibitions now, and not had a good answer. I know there are decoder sites around the place, but they aren't the official word, and it seems to us it would be easly to have a computer decode alongside the TAF or METAR. NOAA seems to manage it automatically on their ftp site, so why can't we? Bernie |
why not print it in English too? Could you imagine if johnny public knew how to respond if fired at with a green flare, given a flare gun and a red and green charge in the cockpit ? There would be a bloody stampede. |
A question we (a group from our club) always ask at exhibitions is - why not print it in English too? |
XL319
wx is always crap at LBA I was up at Durham Tees Valley Airport the other day & one of the ATCOs said that they treat a PROB30 as "It might..." & a PROB40 as "It most likely will...". Not sure how much that was based on fact & how much was an interpretation. Anyone care to comment? |
.......and don't forget that the wind direction is true not magnetic. For those of you who fly a little further a field, it makes quite a differance to the cross wind at the airport when considering landing/take-off. We don't all fly in areas with nearly zero variation. Ours can be up to nearly 60 degrees of variation.:}
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......and don't forget that the wind direction is true not magnetic. After all, METARs and TAFs are used in flight planning, while you are still using true bearings and so forth. But in operating the flight you use magnetic headings so ATC gives the wind in magnetic too. What about VOLMET? |
Yes BP but it's usefull to remember when planning the flight, thats when you use the TAFs and METARS's. Volmets I'm sure are "true" .
WH |
the dreaded weather
Put more simply, if you can't see the windsock, it's raining.
If you can see the windsock it's going to rain ! I too was around Hebden Bridge helping to get the lights back on ! It was quite grimy in parts. :hmm: |
If you get the winds in written form, TAFs, ARFORs, RSWTs, and so forth, the wind is given in degrees true.
If you get the winds in spoken form, ATIS, AWIS, Bloke in Tower, and so forth, the wind is given in degrees magnetic. |
If you get the winds in spoken form, ATIS, AWIS, Bloke in Tower, and so forth, the wind is given in degrees magnetic. |
Because that would start to make flying accessable to all, and after spending £10k on a license I want to be special and able to decode those archaic runes. Ergo, the METAR/TAF codes are actually a form of encryption. Bet most PPL students would agree... :ooh: |
Why can't they just give the weather in plain English?
Is modern technology not capable of something that simple? |
"Why can't they just give the weather in plain English?"
Chuck and others, maybe its because the whole world does not speak English. First the problem with translating it and secondly what does it mean in that region? At least with TAFs and METARs there are definitions of what each group means, which are available, translated into the local language. It just takes application, practice and clarifying what it means with an instructor/experienced pilot, until you get the hang of it. On the other hand they seem to have dummed the TV weather down so I supose a print out of pretty pictures would be OK!:E WH |
A little-known group that you may see will go something like
TX30/14Z TN20/04Z That would be max temp expected 30degC at 1400utc, min 20 at 0400 |
Chuck and others, maybe its because the whole world does not speak English. Hmmmm... .....I thought that English was the international language of aviation. Oh well, I guess it's back to reading the weather in code. :E |
Chuck - if you go to ftp://tgftp.nws.noaa.gov/data/observ...metar/decoded/ you'll find that a rather unimportant tiny little weather organisation called NOAA thinks it is possible to give out decoded METARs on an offical site. No TAFs as yet though.
B |
Excellent - thank you, I'll add a link to my site.
...so, basically NOAA, a not insignifcant player in the weather forecasting world, can manage to translate that which the British Met Office says they can't do. And NOAA is free at the point of use. Mmmm. Bernie |
Hmm.
Aviation Digital Data Service (ADDS) Output produced by METARs form (1812 UTC 10 July 2008) found at ADDS - METARs METAR text: EGSS 101750Z 22018KT 9999 FEW035 18/11 Q1005 Conditions at: EGSS (STANSTED AIRPORT, GB) observed 1750 UTC 10 July 2008 Temperature: 18.0°C (64°F) Dewpoint: 11.0°C (52°F) [RH = 64%] Pressure (altimeter): 29.68 inches Hg (1005.0 mb) Winds: from the SW (220 degrees) at 21 MPH (18 knots; 9.4 m/s) Visibility: 6 or more miles (10+ km) Ceiling: at least 12,000 feet AGL Clouds: few clouds at 3500 feet AGL Weather: no significant weather observed at this time If it's so easy, why does this translator make a patently invalid claim about the ceiling? :E |
'Ceiling' is used in USA/Canada meaning lowest layer of 5 oktas or more.
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Yes - something I hadn't quite grasped....the code which has to be a code because it's international, means different things in different countries.
Mmmmmm - again. B |
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