Mexican METAR
 

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 :confused:

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.]

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! :D

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.

Magnificent, thanks very much!

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

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.

I just use this handy decoder.

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! :D