What does this metar mean ?

PompeyPaul · 10th January 2009, 12:47

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 · 10th January 2009, 12:52

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 · 10th January 2009, 13:44

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 · 10th January 2009, 14:08

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 · 11th January 2009, 00:39

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

flybymike · 11th January 2009, 00:49

Often abbreviated as NNSOGADT

TheGorrilla · 11th January 2009, 00:51

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 · 11th January 2009, 02:51

or simply PS = Pretty Sh*tty.

olderndirt · 6th February 2009, 01:49

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 · 7th February 2009, 10:31

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 · 8th February 2009, 15:38

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 · 12th February 2009, 12:05

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 · 12th February 2009, 14:24

Quote:

...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

Spitoon · 12th February 2009, 14:41

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:

Quote:

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:

Quote:

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.

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