This record includes the two main datasets necessary to run the GSI tutorial presented here: GUESS The 10-member ensemble background files generated using the WRF-ARW numerical model for a regional domain centered in the center and northern Argentina. For more information about the model configuration see https://doi.org/10.1016/j.atmosres.2022.106456 The 00 subfolder includes a 10-member ensemble and the ensemble mean to run the GSI system using the ENKF version. The 01 to 10 subfolders include the background at the analysis time and files every 10 minutes inside the assimilation window to run the GSI system using the fGAT method. OBS Meteorological observations in bufr format. cimap.20181122.t12z.01h.prepbufr.nqc is derived from a prepbufr file available at https://rda.ucar.edu/datasets/ds337.0 plus observations from private automatic meteorological weather networks in Argentina. abig16.20181122.t12z.bufr_d was generated using GOES-16 data available at: The other radiance observations comes from the Global Data Assimilation System (GDAS) Model: https://www.nco.ncep.noaa.gov/pmb/products/gfs/ 1bamua.20181122.t12z.bufr_d ssmisu.20181122.t12z.bufr_d 1bhrs4.20181122.t12z.bufr_d airsev.20181122.t12z.bufr_d mtiasi.20181122.t12z.bufr_d 1bmhs.20181122.t12z.bufr_d atms.20181122.t12z.bufr_d satwnd.20181122.t12z.bufr_d