Mexican METAR

[StopStart]

Dull question I'm afraid and apologies if in the wrong forum but I reckoned you North American types would be most likely to know the answer to this......

What does the "957" in the RMK section of this METAR refer to? I thought I knew all the weird RMK codes but this one has me stumped....

METAR MMMX 141143Z 07007KT 8SM FEW080 16/09 A3030 NOSIG RMK
SLP080 52006 957 8/030 HZY=

Thanks

[Old Boeing Driver]

I think this might be it...

• P is the 3 least-significant digits of mean sea-level
pressure in whole dekaPascals. To the left of the 3
digits, prefix either “9” or “10”, depending on which
one gives a value closest to standard sea-level pres-
sure. For kPa, insert a decimal point two places
from the right. For hPa, insert a decimal point one
place from the right.
Example: 041 means 10041 daPa = 1004.1 hPa =
1004.1 mb = 100.41 kPa. New example: 957 means
9957 daPa = 995.7 hPa = 995.7 mb = 99.57 kPa.
[CAUTION: Some organizations report P in inches of mer-
cury (in. Hg.) instead of hPa. P MSL (in. Hg.) is an altimeter
setting, used by aircraft pilots.]

[StopStart]

Thanks very much but I think that refers to the "SLP***" code in the RMKs...
In this example SLP080 means 1008.0 hPa which is close to the altimeter of 30.30ins. 957hPa is way off. I'll keep searching!

[peekay4]

The 9xx group refers to the 24-hour barometric pressure change in 0.1 hPa increments (similar to the preceeding 5axxx group which is the 3-hour pressure tendency).

So 957 means 5.7 hPa pressure change in the last 24 hours.

[StopStart]

Magnificent, thanks very much!

[Amadis of Gaul]

Sweet King Kamehameha, who reads METARs that far? I'd be done after NOSIG myself.

[MarkerInbound]

At a job interview years back the Chief Pilot pushed a messy METAR across the table and asked what was going on at the station. When I got to the point where I told him how much it had rained in the last hour he pulled it back and was done.

[Amadis of Gaul]

I just use this handy decoder.

[Airbubba]

Years ago the folks from National Airlines in MIA showed me how they read that international weather.

It's called the one finger rule - if you put your finger over the weather and there's still writing below your finger, the weather's bad Airbubba!