Re: GEMPAK5.8.3a: Problems with Canadian METAR and dcmetr

• To: Christian Pagé <page.christian@xxxxxxxxx>
• Subject: Re: GEMPAK5.8.3a: Problems with Canadian METAR and dcmetr
• From: Steve Chiswell <chiz@xxxxxxxxxxxxxxxx>
• Date: 08 Nov 2005 11:29:47 -0700

Christian,

The pressure tendency is decoded from the metar report. However, since
the metar bulletin is not marked as a correction, the decoder will not
attempt to overwrite the already stored values from the SA report.
If you use SFPARM=text, you will see that the metar bulletin was
received and stored.

The problem you have is that the SA report is arriving first, and the
pressure tendency is not being decoded since it is not either the 3 or 5
character group representation that is expected in the airways format.

The behavior to not overwrite data without the correction flag has not
changed. This feature does prevent corrected bulletins from being
overwritten!

Steve Chiswell
Unidata User Support



On Tue, 2005-11-08 at 06:47, Christian Pagé wrote:

Hello everyone,

I am transitioning between GEMPAK 5.7.3 (SGI IRIX) and 5.8.3a (Linux
FC4). I have noticed that on my surface plots, many stations from the
Montreal mesonet transmitted in METAR format in the DDS/IDS feed are
not decoded the same way. In 5.8.3a, I am missing the parameters in
the RMK section, though that in the WMO ascii data the data is the
same (in that particular case only P03C is missing, along with no
tenth precision on temperatures):
368
SACN90 KWBC 081309
METAR CWEW 081300Z AUTO 25007KT 02/M01 RMK AO1 SLP164 T00231012
52017

It is also transmitted in old SAO format, but before (in time) the METAR report:
332
SACN90 CWAO 081300
WEW SA 1300 AUTO8 M M M 164/02/-01/2507/M/ 2017 32MM

The P03C group is 52017 in METAR format in the RMK section. I get in SFLIST:
    WEW    051108/1300   1016.40 -9999.00     2.00    -1.00     7.00   250.00
                        -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                        -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                        -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                        -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                        -9999.00
instead of:
    WEW    051108/1300   1016.40 -9999.00     2.30    -1.20     7.00   250.00
                        -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                         2017.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                        -9999.00 -9999.00     1.70 -9999.00 -9999.00 -9999.00
                        -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
                        -9999.00

What did change??

--
Christian Pagé
UQAM

• References:
  • GEMPAK5.8.3a: Problems with Canadian METAR and dcmetr
    • From: Christian Pagé