Re: 20020627: Synoptic Code max/mins

Jeff,

The information is in the WMO manual on codes (No. 306) Volume II
(Regional Codes and National Reporting Practices).

As an example, For region VI, it says for section 3, Group 1SnTxTxTx
this group shall be included at 1800UTC to report the maximum daytime
temperature of the preceeding 12 hours (0600 to 1800).

For region 4, the group is:
at 0000Z and 1800Z the previous 12 hour max
at 0600Z the previous 24 hour max
at 1200Z the previous calenday day max

Gempak uses 2 tables:
                        00Z 06Z 12Z 18Z

        DATA  mintbl  / 99, 12, 99, 99,
     +                  12, 12, 12, 12,
     +                  99, 99, 12, 99,
     +                  18, 24, 12, 24,
     +                  24, 99, 99, 99,
     +                  99, 12, 99, 99,
     +                  12, 99, 12, 99/
C*
        DATA  maxtbl  / 99, 99, 99, 12,
     +                  12, 12, 12, 12,
     +                  12, 99, 99, 99,
     +                  12, 24, 24, 12,
     +                  99, 99, 24, 99,
     +                  99, 99, 99, 12,
     +                  12, 99, 12, 99/


showing what is reported at each of the 4 synoptic times for the 7 WMO regions.

Looking at maxtbl, you see for region 6 (aka line 6): 99, 99, 99, 12.
Meaning that at 0, 6, 12 it is not defined. At 18Z it is the 12 hour max

For region 4: 12, 24, 24, 12,  meaning at 0Z and 18Z it is a previous 12 hour
max, and at 6 and 12, a 24 hour max.

As you can see, it is apples to oranges when trying to plot a map
showing values in different WMO regions.

Steve Chiswell






On Fri, 28 Jun 2002, Jeff Masters wrote:

> Hi Chiz, I went to the WMO web site to try to find this publication, and
> found a reference to the manual on codes 306, and another WMO manual
> 386. Neither is available on-line or at the library here, so I'll have to
> order this. Can you tell me which to order? Or do you have a copy of the
> Gempak routine that is readable enough to be able to figure out what
> countries use which max/min periods?
>
> Thanks, Jeff
>
> On Thu, 27 Jun 2002, Steve Chiswell wrote:
>
> >
> > Jeff,
> >
> > The WMO manual on codes 386 part II addresses regional reporting practices
> > including the time period that the max/min is valid for. The GEMPAK dcmetr
> > decoder takes these differences into account as to what time is assigned to
> > the max/min value.
> >
> > Steve Chiswell
> > Unidata User Support
> >
> > On Wed, 26 Jun 2002, Jeff Masters wrote:
> >
> > >
> > > I've been looking at the max/mins reported in the synoptic code obs across
> > > the world, and have discovered that the "standards" for reporting max/mins
> > > vary widely from one country to the next. For example, the UK reports a
> > > min at 6Z for the 12 hour period ending at 6Z. Iceland reports mins at 9z,
> > > presumably for the 12 hours ending at 9Z. But in Canada, the min reported
> > > at 18Z is the 24 hour min, and the max reported at 12Z is the 24 hour max
> > > for the period 6Z to 6Z. Does anyone know of a list of the various
> > > international standards for reporting max and mins?
> > >
> > > Thanks,
> > > ------------------------------------------------------------------------------
> > >  Jeff Masters
> > > (address@hidden)                                             (  )
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> >
>