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[CONDUIT #CQQ-962463]: CONDUIT GRIB-2's for GFS 0.5 deg

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  • Subject: [CONDUIT #CQQ-962463]: CONDUIT GRIB-2's for GFS 0.5 deg
  • Date: Fri, 21 Jul 2006 09:52:47 -0600
> Hi,
> I was examining the CONDUIT grib-2 files for the GFS 0.5 deg model found at
> ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnt/MT.gfs_CY.12/RD.20060720/PT.grid_DF.gr2/
> Specifically, I downloaded the file fh.0054_tl.press_gr.0p5deg_.
> _But within the contents of the file I found that there were also
> 48-hour forecasts contained in this file along with the 54-hour
> forecasts (a little over 5 M of the total 38 M file)
> Is this something that is known?
> Thanks!
> Kevin
> 
> 

Kevin,

I decoded the fh.0054_tl.press_gr.0p5deg file for July 20, and in fact, all 
grids are F054
as decoded in GEMPAK (gb2ftim.c routine).

I suspect your confusion arises due to the the way the time is presented in 
Product Definition Template 4.8 in GRIB2 for accumulations (Precipitation, max 
temp etc for example).
PDT4.8 Provides a "End time" of the overall period (which is the 54 hour 
forecast time verification).
The "48" you will find in in the forecast time would be the time at which the 
accumulation, average or
extreme period begins since the start time of the model. The 48 by itself 
outside of the context
of the product definition template which is necessary for decoding is amorphous.

As in the case of precipitation accumulation, the value is accumulated over the 
6 hours, and that
value is the accumulation at the end of the period.

I'm glad that you are looking in to this data set, as we are about to extend 
the period delivered to
CONDUIT through 180 hours (using the ftpprd ncep files rather than the tgftp 
file names though).

Steve Chiswell
Unidata User Support

Ticket Details
===================
Ticket ID: CQQ-962463
Department: Support CONDUIT
Priority: Normal
Status: Closed