Choosing the right GFS (grib2) files

[apo]

Hello,
Βelow I describe the scenario that I want to run in WRF.
It is 9/01/2025 21:00 UTC and I want to run the WRF model for a 48 hour forecast. That is 10/01/2025 21.00 - 11/01/2025 21:00
In NCEP GFS 0.25 there are grib2 files from gfs.0p25.2025010800.f000.grib2 to gfs.0p25.2025010818.f384.grib2.

NCAR RDA Dataset d084001

NCAR RDA

rda.ucar.edu

I am confused about which grib2 files I should use.

The gfs.0p25.2025010800.f000 - gfs.0p25.2025010800.f048.grib2 ???

or the most recent ones, i.e. gfs.0p25.2025010818.f000.grib2 - gfs.0p25.2025010818.f048.grib2 ???

or some others?

Thank you.

 

[Ming Chen]

The name of gfs file has specific meaning. Let's take gfs.0p25.2025010800.f000 and gfs.0p25.2025010800.f048.grib2 as example:
2025010800 indicates initial time of GFS forecast, f000 indicates this is 00hr forecast, in another words, this is the initial data for GFS run. f048 indicates this is 48-hr forecast of GFS initialized at 2025010800.
This is the convention of GFS datafile naming. Let me know if you still feel confused.

 

[apo]

First of all, I want to thank you so much for your answer.

Although it is clear to me now what the name of each file means, I am still confused about which files I should download each time. To use the example I mentioned above, let's say that it is now 9/01/2025 21:00 UTC and I want to run the model for a 48-hour forecast (with a history interval of 180).
Should I use
a) only gfs.0p25.2025010800.f000 and gfs.0p25.2025010800.f048 grib2 files (2 files) ?
or
b) All files from gfs.0p25.2025010800.f000 - gfs.0p25.2025010800.f048 (16 files) ?

The model runs in both cases and gives the following output, but I don't know which method is correct.

wrfout_d01_2025-01-09_00_00_00, wrfout_d01_2025-01-09_03_00_00 .... wrfout_d02_2025-01-09_00_00_00, wrfout_d02_2025-01-09_03_00_00 .......... wrfout_d02_2025-01-11_00_00_00

Thank you