Documentation for NOAA GFS output files

Question

I am interested in getting the GFS forecast data for Europe which is available for free from the following website.

Link to GFS Forecasts

The data can be downloaded from here

I just need the data for the Europe (Germany to be exact). While Reading the grb file, I found that the data-set is huge and has dimension of 65160 352

grib <- readGDAL("gfs_3_20170215_1800_000.grb")

I was looking for the documentation for the file. What does the each column mean? and such. If you happen to know anything about it, please let me know.

Answer 1

If you want to know the meaning of each variable, check this:

Parameters & units: http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.html

Answer 2

first of all, the best place to download grib2 files of GFS is this: GRIB2 filter

With this website you can select the variables, levels, region... of the weather forecast.

The format GRIB2 is the new version of GRIB, a little different but there are many weather models who use this new format.

To read the information, you need to install the wgrib2 utility. This is so easy to use it! Only open the console and write:

wgrib2 GFS-file.grib2 -match ":TMP:2 m above ground" -lon 2.15 41.42

After use this command, it will return all the temperatures at 2m above ground for the coordinates 2.15 and 41.42

Answer 3

The GFS data is available from NCEP's NOMADS site and is designed to be scripted so that you can extract just the variables AND the LAT/LON dimenions you want.

So for Germany you could specify a square "Subregion" around just the country. It will be a much smaller Grib file.

Here is the URL to the page that allows your pull the data and specify the LAT/LON "Sub Region"

http://nomads.ncep.noaa.gov/cgi-bin/filter_gfs_0p50.pl

http://nomads.ncep.noaa.gov/cgi-bin/filter_gfs_0p50.pl?dir=%2Fgfs.2017060100