11 March 2016

ds083.3: GDAS/FNL 0.25 degree global grids

Since July 8, 2015, RDA has been archiving 0.25 degree  GDAS/FNL analysis and forecast (hours 3, 6, 9) globally gridded data in GRIB2 format.

We call it ds083.3: NCEP GDAS/FNL 0.25 Degree Global Tropospheric Analyses and Forecast Grids.

I hope you call it useful.  ;-)

The analysis files are named gdas1.fnl0p25.YYYYMMDDHH.f00.grib2.

You may be able to find and download FNL at this resolution from NCEI beginning in mid-January 2015, but the RDA archive begins in July 2015 with gdas1.fnl0p25.2015070800.f00.grib2.

Forecast grids corresponding to 3, 6 and 9 hours after analysis time are named gdas1.fnl0p25.YYYYMMDDHH.fFH.grib2 where Forecast Hour, FH, can be 03, 06, 09.

wrfhelp@ucar.edu expects most WRF users will see forecast improvement with 0.25 degree instead of 1.0 degree input.  You can use a series of f00 analysis files to provide initial conditions and lateral boundary conditions for your WRF run.  You can also add forecast files to extend your WRF run past the time of the latest available FNL analysis file.

Each 0.25 degree GDAS/FNL analysis file is about ~180 MB while the corresponding 1.0 degree file is  ~17 MB.

Also note that the forecast 0.25 degree grids are ~205 MB because they include water (APCP, ACPCP, PRATE...) and cloud variables that are not in the analysis grids.  This is why some people call the analysis grids "dry".

Please order subsets of the global grids in order to efficiently use shared bandwidth.

We will not be back-filling the 0.25 degree GDAS/FNL to Jan 2015.  If you need FNL files we don't offer, order them directly from NOAA.


  1. Hi,

    I am Mendi from Indonesia. I am new to this satellite things. I have download and process these files and it really helps me on my thesis about solar radiation. I have question, is there any number of accuracy for Downflux shortwave radiation of this files?

    thanks in advance, wait for your reply.

    1. This comment has been removed by the author.

    2. Mendi,
      In which file of ds735.0 did you find this field? For faster response, please follow the steps in http://ncarrda.blogspot.com/2015/12/best-practices-when-asking-for-help.html

  2. Hello,

    My name is Ardhi from UTokyo. I'm currently using WRF V.3.8.1 and intending to run 24h simulation by using FNL data as the input. As you said, FNL only provide f00 to f09 data, and we might use GFS forecast for the rest (f12-f24).

    My question is, how do I set WRF's ungrib for this purpose since FNL and GFS both have their own Vtable? Should I individually ungrib them e.g. f00-f09 using FNL Vtable-ungrib, then continue with GFS f12-f24 using GFS Vtable-ungrib.

    Thank you.

    1. You can use the same Vtable. Download it from http://www2.mmm.ucar.edu/wrf/users/download/free_data.html


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