Translation help please

[ianboag]

What does the 1AC140 and 6AC160 etc bit of this METAR mean?

 

RMK RF00.0/000.0 1AC140 6AC160 FM0930 MOD TURB BLW 5000FT

 

Is it something to do with an incoming flight of six Jabirus and a single Cherokee 140 ...... ?

 

 

[flying dog]

The RMK RF line is Rain Fall

 

There is a link (somewhere on this site) which gives you both the weather report and an English translation.

 

Sorry I don't have it off the cuff.

 

 

[flying dog]

Australian AVMET

 

Try that.

 

 

[Admin]

Recreational Flying - Weather, all about understanding METAR

 

 

[slartibartfast]

I can't see where either of those resources (as good as they are - especially ours) answers the question.

 

My guess is that it refers to cloud.

 

Code Low Clouds Middle Clouds High Clouds

 

---- --------------- --------------- ---------------

 

0 None None None

 

1 Cu (fair wx) As (thin) Ci (filaments)

 

2 Cu (towering) As (thick) Ci (dense)

 

3 Cb (no anvil) Ac (thin) Ci (often w/Cb)

 

4 Sc (from Cu) Ac (patchy) Ci (thickening)

 

5 Sc (not Cu) Ac (thickening) Ci/Cs (low in sky)

 

6 St or Fs (fair) Ac (from Cu) Ci/Cs (hi in sky)

 

7 Fc/Fs (bad wx) Ac (w/Ac,As,Ns) Cs (entire sky)

 

8 Cu and Sc Ac (w/turrets) Cs (partial)

 

9 Cb (T-storm) Ac (chaotic) Cc or Cc/Ci/CsAc-Altocumulus, As-Altostratus, Cb-Cumulonimbus,

 

Cc-Cirrocumulus, Ci-Cirrus, Cs-Cirrostratus, Cu-Cumulus,

 

Fc-Fractocumulus, Fs-Fractostratus, Ns-Nimbostratus,

 

Sc-Stratocumulus, St-Stratus

 

(wx = weather)

 

 

So, 1AC140 might mean thin Altocumulus at 14,000 feet, and 6AC160 might be Altocumulus from Cumulus at 16,000 feet.

 

 

[ahlocks]

...So, 1AC140 might mean thin Altocumulus at 14,000 feet, and 6AC160 might be Altocumulus from Cumulus at 16,000 feet.

The first numeral is cloud cover in oktas. (eighths of the sky)

 

1-2 = FEW

 

3-4 = SCT (scattered)

 

5-7 = BRN (broken)

 

8 = OVC (overcast)

 

I.e 1AC140 = 1 octa (few) AltoCumulus at 14000ft

 

I saw it explained somewhere but can't for the life of me remember where...

 

 

[ianboag]

Thanks. Sounds as reasonable as anything - I'd never seen it before despite running heaps of METARs through the translator. Someone at YSSY had a bit of a brain spark it seems.

 

I'll educate the program some more.

 

 

[facthunter]

Mmm.

 

I'd go along with ahlocks. 1 octa Altocumulus at lvl 140 & 6 octas altocumulus at 160.N..

 

 

[slartibartfast]

Yeah - me too. That was my second thought and makes a lot more sense than my first thought. Which makes me wonder why it didn't override my first thought, and to wonder how often I ignore better thoughts because of temporal precedence.

 

 

[Captain]

Ian,

 

I have checked it out in great detail, and you were right.

 

It is definitely a Cherokee and six Jab's ...... inbound, on descent, with their stereos at 8 octaves.

 

Hope this helps.

 

Regards Geoff

 

 

[ianboag]

Just to clarify one more thing for me in that Sydney METAR ...

 

.... FM0930 ...

 

I suppose that having just a 4-digit group here is an error ? And it's UTC of course? "Today" whatever that means ....? In which case my translator will just leave it alone .....

 

 

[Guest Decca]

That's FROM 0930 UTC Ian. Not sure what you mean by "today", but guessing that's an interpretor function/statement.

 

Decca.

 

 

[ianboag]

The syntax of <FM> is <FMhhmmdd> ie FM-hour-minute-day. The group there is missing "day". I agree that one could make an intelligent guess ......

 

 

[flying dog]

Hang on....

 

hhmmdd??!!

 

Hour Minute Day?! Nah. Surely not.

 

It would be Date Hour Minute. (Or "Date/Time/Group" as I learnt it in other parlance.)

 

 

[facthunter]

HMMm!

 

Think it's day , hours minutes. (all UTC or Zulu in the old parlance). N...

 

 

[ianboag]

Friggin brain fade. Comes with getting old.

 

FM0930 would be the 9th of the month at 30 hrs with the mins unspecified. Hmm. I think not. Looks like the METAR author slipped a cog .... Perfection is such a rare commodity these days. This was a YSSY METAR a couple of days ago that someone pointed out to me as containing stuff the xlator didn't know what to do with ....

 

 

[facthunter]

Perfection?

 

Wouldn't the ability for it to be understandable and ACCURATE be good. I think they have left some of it out. Don't feel you have brain fade at all. I have done this stuff for years so I have no excuse. I HATE it. The times are most important as they will affect when an operational requirement starts and finishes, so they must be right. Nev..

 

 

[ianboag]

Yeah - realistically - a human can make a pretty reasonable guess at what it means, but it's a dog of a thing to make a computer program do. There are so many possible errors that could happen ......

 

 

[flying dog]

"....but it's a dog of a thing ......"

 

(Accent required)

 

What you talkin' about Willis?

 

;)

 

Ok, sorry.

 

 

[flying dog]

Actually I'd disagree with you slightly Ian.

 

I would attack it by parsing the line.

 

If it is a METAR, parse it one way, if it is a TAF, parse it another.

 

I know that may be a bit over simplistic way to explain it, but do you see how I would go about it?

 

go through the text in "blocks" and parse the lines in the text accordingly.

 

Ofcourse you would need to find a "terminator" for each parragraph, but I'm guessing that a couple of blank lines would suffice.

 

BTW, how are you doing this? What language? HTML, what?

 

 

[ianboag]

It's done in PHP and works more or less as you describe. ARFORs are quite a job as they have lots more scope and cover more ground.

 

My point about mistakes was I can pull out FMddhhmm OK and translate it, but it gets a whole lot harder when I run into FMxxxx and have to write code to guess which two characters are missing and what "reasonable" values should be used for them. So I don't bother - if there's a mistake (like this one) I just leave it in uppercase ......

 

 

[flying dog]

PHP?

 

I wouldn't know what that is if my life depended upon it.

 

 

[Guest Mad Dave]

Ian,

 

Where there is the FMxxxx code as you have described the full UTC010100 code will have already been given earlier in the report, so it really woudn't be that hard for the reader to figure out what was going on if you left it.

 

Dave

 

 

[Bryon]

A simple question......why have a code at all, if everyone is trying to translate it and having trouble, why not just have it in plain engrish

 

 

[ianboag]

As the person who wrote the translator I'm not the best one to ask.

 

I have been for a visit to MetService (the NZ BOM equivalent) and watched forecasters writing TAFs straight off the top of their heads. Use of the ICAO codes by the forecasters does ensure a degree of consistency in what the forecasts mean. A plain language translation of the (consistent) codes ensures a degree of understanding of what the forecasts say.

 

Choice is good. Those who are most comfortable with Met-jibber and UTC can read their weather that way and be happy. Those who prefer English can have it like that and be happy too.

 

Whatever works best for you ... it's like Catholic Mass - Latin or vernacular. Horses for courses .....