20000523: AVN grid decoding by McIDAS-XCD

>From: Eirh-Yu Hsie <address@hidden>
>Organization: CU/CIRES
>Keywords: 200005231606.e4NG6NT07313 McIDAS-XCD GRID decoding DMGRID 
>gbtbpds001.av1 RTMODELS.CFG

Hsie,

Sorry I couldn't get to this before this morning, but I was on travel until
last night.

>I can not figure this out.  "dmgrid.k" will not docode AVN beyond 72 hours.
>My AVN entry in /home/mcidas/workdata/RTMODELS.CFG is:
>
>AVN=  3 5401 120000 240000 1200000

This is correct.

>and my AVN entry in /home/mcidas/workdata/RESOLV.SRV is 
>
>N1=RTGRIDS,N2=AVN,TYPE=GRID,RT=Y,K=GRID,R1=5401,R2=5500,C=Real-Time AVN Grids,

This is also correct.

>cumulus:[62]% igu.k LIST 5401 5500
> GRIDFILE   PROJ  CREATED MAXGRD IDENT
> --------   ----  ------- ------ ----------------
>   5403        0  2000143  5000  ALL  00Z AVN 0  HR<=VT<=24 HR
>   5404        0  2000144  5000  ALL  00Z AVN 0  HR<=VT<=24 HR
>   5413        0  2000143  5000  ALL  00Z AVN 24 HR< VT<=48 HR
>   5414        0  2000144  5000  ALL  00Z AVN 24 HR< VT<=48 HR
>   5423        0  2000143  5000  ALL  00Z AVN 48 HR< VT<=72 HR
>   5424        0  2000144  5000  ALL  00Z AVN 48 HR< VT<=72 HR
>   5453        0  2000143  5000  ALL  12Z AVN 0  HR<=VT<=24 HR
>   5454        0  2000144  5000  ALL  12Z AVN 0  HR<=VT<=24 HR
>   5463        0  2000143  5000  ALL  12Z AVN 24 HR< VT<=48 HR
>   5464        0  2000144  5000  ALL  12Z AVN 24 HR< VT<=48 HR
>   5473        0  2000143  5000  ALL  12Z AVN 48 HR< VT<=72 HR
>  ---END OF LISTING

The problem is caused by the change in PDS octet 6 values for the AVN files.
(The same is true for MRF files).  I put out a -X, -XCD addendum on
May 18, but I was not able to document it in the unix/760/bugfix/README
or online Addenda information until this morning.  In particular, the
file gbtbpds001.av1 has modifications that are needed to decode the
AVN forecast grids out to 120 hours.

The following exerpt of an update I received from SSEC summarizes this
change:

  On 16 May 2000, the National Weather Service implemented the
  three changes listed below.
  
     * the generating model ID number for the MRF T170L42 will be changed
       from 78 to 94
     * the generating model ID number for the AVN will be changed from 77
       to the generic value 96 for forecast hours 0 through 120
     * forecast hours 78 to 120 in 6 hour time steps for the AVN model
       will be added to the AWIPS/NOAAPORT data stream
  
  Although the change to model numbers 94 and 96 should not prevent
  the AVN and MRF grids from being successfully decoded and filed, the
  grids will have an "x" in the grid header label instead of the proper
  3-character label, "AVN" or "MRF". If you decode the AVN model, the
  amount of disk space required to store this data will be higher due
  to the additional forecast hours.

The procedure you can follow to update your XCD GRID decoding is contained
in:  http://www.unidata.ucar.edu/packages/mcidas/mcx/addenda_000518.html

Tom

>From address@hidden Thu May 25 10:38:42 2000
>Subject: Re: 20000523: AVN grid decoding by McIDAS-XCD 

Hello, Tom:

I made the modification for gbtbpds001.av1 couple of days ago.  All the
data are filed correctly up to 72 hours.  I install the update this
morning.  Let me wait and see what happen.  There are some typos in the
addenda web page:

zcat mcunpack.tar.Z | tar xvf - ../data/gbtbpds001.av1
     ^^^^^^^^
     mcupdate
     
rm gtbtpds001.av1 gbtbpds001.2v* RTMODELS.CFG
   ^^^^^^^^^^
   gbtbpds001
   
   
   Hsie

>From address@hidden Thu May 25 11:21:40 2000
>Subject: Re: 20000523: AVN grid decoding by McIDAS-XCD 

>Hello, Tom:

re: decoding of AVN grids out to 120 hour forecast

>I find out what my problem is.  I only decode thin grid for ANV model.
>The thin grid is only up to 72 hours.  Thank for your help.

>Hsie