What does this metar mean ?

[PompeyPaul]

EGLF 101220Z 25005KT 1600 R24/P1500 BCFG BR OVC002 M04/M04 Q1027

I've not seen R24/P1500 before ? Is it runway 24 visibility 1500m ? If so how is that different from RVR ? I looked at the glossary but can't see anything for it.

[Kiltie]

R24 is an RVR figure for runway 24; the "P" stands for "increasing."

1600 is the Met Vis.

Met Visibility and RVRs are measured by seperate methods. The two are not expected to be equal.

[Red Four]

P does not stand for increasing!!
It indicates the RVR is in excess of the maximum that can be read for a particular runway.
D (decreasing), U (increasing) not presently used in UK, but are in rest of Europe. There is also a code for staying the same (which I cannot recall at present).

[fisbangwollop]

P1500=Runway Visual range greater than 1500metres. The RVR is measured by a set of either visual lights or elecronically by a set of transmisometers set along the edge of the runway.......the aerodrome visibility may often be differant from the runway visibility. RVR's are usually also quoted for Touchdown, midpoint and stop end.

[TheGorrilla]

It means it's time for numbnuts to stay on the ground and drink tea. :rolleyes:

[flybymike]

Often abbreviated as NNSOGADT

[TheGorrilla]

So that explains something else on the METARS and TAFs.

P.s. If I were being picky I'd say transmissometers has 4 Ss in it.

P.p.s. PS on a METAR = Pea Soup??

[Say again s l o w l y]

or simply PS = Pretty Sh*tty.

[olderndirt]

Metar means we lost our old airways code which was just like a favorite pair of slippers. I know, we were probably the only country out of step but I still miss it.

[Fright Level]

As R4 says, it means greater than 1500m. That is the upper range of most transmissometers used so it just means that they are using them as well as tower visibility (1600m in this example) to back up the vis report.

[FDR man]

RVR is given only when horizontal visibility (or RVR itself) is less then 1500m. If RVR is more than this 1500m. a P is added in front. Here R24/P1500.

When letters are shown after this it indicates a trend over a period of 10 mins, as correctly said by Red Four.

"There is also a code for staying the same (which I cannot recall at present)."

It is then P1500N

[moggiee]

Surely there's no need to include the RVR in this METAR?

For one, at 1600m met vis then there are unlikely to be many instrument approach restrictions and second an RVR which is LOWER than the met vis (because the RVR can't read greater than 1500m) is about as useful as the proverbial chocolate teapot.

By the way, I did see chocolate teapots for sale in a sweet shop in Le Touquet a couple of years ago - I have a picture somewhere.

[Floppy Link]

...at 1600m met vis then there are unlikely to be many instrument approach restrictions ...

In this case the METAR also states BCFG (fog patches) - and it's RVRs that we use for approach minima - sod's law says that the fog patch will be just where you don't want it - at the RVR transmissometer :hmm:

[Spitoon]

The rules for METAR coding in the UK (which do not include all reported elements that are possible) are published in CAP 746.

On the basis of these rules the METAR in question appears to be incorrect in that the RVR value should not have been included.

The relevant extracts from CAP 746 are:

The RVR group shall be reported in the METAR only when either the minimum visibility or the runway visual range is observed to be less than 1500 metres.
2000 metres should be regarded as the maximum value that is possible to report. If the actual value is greater than can be reported by the runway visual range equipment or human observed method, the maximum value shall be preceded by ‘P’.
However, the rules for reporting IRVR to aircraft by ATC are slightly different. CAP 493 (a.k.a. MATS Part 1) says:
IRVR reporting to aircraft is started:
a) whenever the aerodrome meteorological report shows the visibility to be less than 1500 metres;
b) whenever the IRVR display is indicating an RVR value equal to or less than the maximum for that system;
c) whenever shallow fog is reported and during a period for which it is forecast.

So it looks like the METAR has been coded up using the rules for passing IRVR reports to aircraft by ATC.

[Krits]

TAF AMD KRIV 2705/2804 05012KT 9999 SKC WSCONDS QNH3008INS
BECMG 2716/2717 03009KT 9999 SCT200 QNH3011INS WND 320V070
TEMPO 2720/2801 03012G18KT
BECMG 2801/2802 VRB06KT 9999 SCT200 QNH3004INS T21/2721Z
T03/2715Z AMD 270511=

Can anyone explain to me what QNH3008INS means? Firtly, why is there a 3 in there? Secondly what does that INS mean?

Finally. T21/2721Z. Is that like saying temperature is 21 at 21 Zulu on 27th?

Thanks :)

[The500man]

My best guess is that the QNH is 30.08 inches? I don't think TAFs incude temperatures do they?

[Krits]

Oh crap. Thats right. I've been looking at QNH's in Hpa all day that I completely forgot about Inches in Mg. Whoops.

Why can't everyone just use the same damn thing.

[Crash one]

30 point 08 inches of mercury I believe? How that is converted to Millibars I can't remember.
Edit: everyone beat me to it (must learn to type)

[Krits]

Yeah, got that. But any idea what INS stands for?

EDIT: And since it is given in Inches of MG. Shouldn't it have been preceded with an "A" instead of a "Q"?

[Crash one]

INS = Inches

[The500man]

Found ths converter for Inches to Millibars: Inches-Millibars Pressure Converter (http://www.csgnetwork.com/pressinmbcvt.html)

[Crash one]

Excellent!!!

[englishal]

Don't most altimeters have inches and mb displayed?

29.92 = 1013.3

[Jan Olieslagers]

I don't think TAFs include temperatures do they?

Don't think so, either. And the same applies to QNH, in my experience.

[JW411]

krits:

T21/2721Z T03/2715Z

This does indeed mean that the maximum expected temperature at this airfield is likely to be 21 degrees and is estimated to happen at 2100Z on the 27th.

Likewise the minimum temperature is expected to be 03 degrees at 1500Z on the 27th.

This is useful information for projected take-off performance purposes. (The higher the temperature - the lower the possible take-off weight from a given runway).

In the old days, aircraft like the Tu104 couldn't even get airborne from airfields such as Bahrain in the summer until the temperature went down after dark!

[Krits]

JW

Thank you for that :). I had assumed that it meant the high and low Temps, but wanted a confirmation.

Its amazing seeing how METARS/TAF can change place to place. Not much difference, but still enough to put a few doubts in your head.