Topic: TAF is what is left out unchanged?

[Hellis]

Hello!

New member here from Sweden.

Example:
201113Z 2012/2112 20014KT 9000 BR FEW008 TEMPO 2018/2109 4000 BKN008 TEMPO 2109/2112 23015G25KT=

The visibility is reduced from 9000 to 4000 m, but what happens after 2109? Is it still 4000 m visibility?
Same thing with clouds? It gets cloudier on the same altitude, but what happens after 2109?

Would it be correct to believe the clouds and visibility is unchanged?


The reason I ask is I'm building a translator for TAF/METAR.

[meteo-saint-brevin]

Hello,
The visibility is reduced from 9000 to 4000 m from 20th at 18UTC to 21th at 09UTC and supposed to be CAVOK (Ceiling and Visibility OK) after that. But windy. 

Please have a look on how does Allmetsat decode METAR and TAF messages in Swedish for Stockholm Arlanda ESSA
http://sv.allmetsat.com/metar-taf/europa.php?icao=ESSA

I use a free php script by Beteljuice to decode TAF on one of my forecast pages.
http://www.meteo-saint-brevin.fr/previsions5.htm

Since it is a little bit old (2009), I could not find a link to download it now. If you are interested, please drop me a private mail and il will send it to you.

[Hellis]

Hello and thank you for your reply.

Thank you for your offer on help with a php library.
I used a old version from 2006 and have upgraded it heavily to meet todays reports.
So I have a working code that translates everything in both METARS and TAFs.

I know of allmetsat, and have looked at their page in the past, but never actually on the translated version.
But it seems they too leave out what is not in the TAF.
Which I can understand. Because the report does not say more.

But the issue I have is that I have a picture function.
It outputs a picture of what the weather will look like.
CAVOK shows clear skies and a sun, OVC clouds shows only clouds, fog shows (sorry for my lack of better words) a dimmed sun, and rain shows rain etc.
And this picture is generated depending on the clouds, current weather, and visibility.

So on most reports it works great, but sometimes they only show the wind as in the above example and I can't display a picture of wind (yet ).

This is why I wonder if I can use the previous TEMPO visibility and current weather etc. if it's missing.
Or does it mean CAVOK as you say.

Looking at METARs from (ESMS) 2109/2116 they say clouds and increasing visibility.

This may have been a hard report for them to set and that is why they left it out.


Anyways. The problem is not really reading what is in the report it's what is not there. Are there any guides they follow?

[meteo-saint-brevin]

Don't forget TAFs are first made for pilots and not for personal weather stations owners to have a nice website.

I remember when I was a plane pilot i used to ask the met center before a fly for the metar and taf of destination and waypoints.
The metar and taf where in text form and we did not have a decoder and yet they where easily understood.

When developing my weather website, I wanted to show Taf decoded to my visitors and then I was surprised how difficult it is to make a good decoder giving well structured sentances in common language.

I would be pleased to see your decoder working on your website.
Regards

PS : There is a lot a windy icons on the web. Ask Google 

[Hellis]

Don't forget TAFs are first made for pilots and not for personal weather stations owners to have a nice website.

I remember when I was a plane pilot i used to ask the met center before a fly for the metar and taf of destination and waypoints.
The metar and taf where in text form and we did not have a decoder and yet they where easily understood.

When developing my weather website, I wanted to show Taf decoded to my visitors and then I was surprised how difficult it is to make a good decoder giving well structured sentances in common language.

I would be pleased to see your decoder working on your website.
Regards

PS : There is a lot a windy icons on the web. Ask Google 

I agree that it is very hard to get a good grammar on a generated weather report.
I think I have managed fairly well, there is always room for improvments but it does look good in my opinion.

Before you click on any of the other links you need to set up the webpage for your needs.
Click on the "settings" icon at the top right.
To make it easy for us lets just say: put all radiobuttons to "Ja" which is yes. If you choose metric or imperial measurement does not change the M/T, it's for another part of the page.
And tick the box that you agree on using cookies to store your settings. The cookie can be removed from the settingspage if you visit it again.

www.hoppvader.nu

The page is in swedish, but maybe google translate can help you.
Keep in mind this page is not meant for pilots who fly passengers from A-B.
The page is meant for pilots and skydivers who operate at one airport. Metars and tafs are taken from nearby stations to see what is comming.

Text form M/T is not too hard to read, for me.
But it could be because I have done this page and learned along the way.


I don't like grabbing pics from the net and using them.
Either it needs to be free pics or I need to make them myself.
Maybe I will try to draw a windsock on the images, but I think that will be hard to make it look good.

[meteo-saint-brevin]

Very nice work ! Congratulations