This file documents the directory structure and file naming conventions for the model input data in
this directory, for use with the UFS SRW App.

The FV3GFS directory contains output data from the GFS model v15 or later (using the FV3 dynamical
core). There are multiple subdirectories which separate the different file formats that FV3GFS data
can be provided in: grib2, nemsio, and netcdf (not currently used)

Under the subdirectory for file format, the files are separated by the initial forecast time of the
input data. For example, the directory 2019061500 contains data from a GFS forecast initialized at
00z on 20190615; shortly after GFS v15 was released.

The filenames are the same as found on HPSS data stores. For grib2, the format is 

gfs.t{hh}z.pgrb2.0p25.f{fhr}

where {hh} is the 2-digit UTC hour of forecast initialization, and {fhr} is the 3-digit forecast 
hour. For nemsio, the format is different depending on whether the file is from the initial
time or a forecast output.

Initial conditions:
gfs.t{hh}z.atmanl.nemsio (atmospheric fields)
gfs.t{hh}z.sfcanl.nemsio (surface fields)

Forecasts:
gfs.t{hh}z.atmf{fhr}.nemsio

FV3GFS
  grib2
    2019061500
      gfs.t00z.pgrb2.0p25.f000
      gfs.t00z.pgrb2.0p25.f003
      gfs.t00z.pgrb2.0p25.f006
      gfs.t00z.pgrb2.0p25.f009
      gfs.t00z.pgrb2.0p25.f012
      gfs.t00z.pgrb2.0p25.f015
      gfs.t00z.pgrb2.0p25.f018
      gfs.t00z.pgrb2.0p25.f021
      gfs.t00z.pgrb2.0p25.f024
      gfs.t00z.pgrb2.0p25.f027
      gfs.t00z.pgrb2.0p25.f030
      gfs.t00z.pgrb2.0p25.f033
      gfs.t00z.pgrb2.0p25.f036
      gfs.t00z.pgrb2.0p25.f039
      gfs.t00z.pgrb2.0p25.f042
      gfs.t00z.pgrb2.0p25.f045
      gfs.t00z.pgrb2.0p25.f048
    2019061518
      gfs.t18z.pgrb2.0p25.f000
      gfs.t18z.pgrb2.0p25.f006
    2020081000
      gfs.t00z.pgrb2.0p25.f000
  nemsio
    2019070100
      gfs.t00z.atmanl.nemsio
      gfs.t00z.atmf003.nemsio
      gfs.t00z.atmf006.nemsio
      gfs.t00z.sfcanl.nemsio
    2019070112
      gfs.t12z.atmanl.nemsio
      gfs.t12z.atmf003.nemsio
      gfs.t12z.atmf006.nemsio
      gfs.t12z.sfcanl.nemsio
    2019070200
      gfs.t00z.atmanl.nemsio
      gfs.t00z.atmf003.nemsio
      gfs.t00z.atmf006.nemsio
      gfs.t00z.sfcanl.nemsio
    2019070212
      gfs.t12z.atmanl.nemsio
      gfs.t12z.atmf003.nemsio
      gfs.t12z.atmf006.nemsio
      gfs.t12z.sfcanl.nemsio

The FV3GFS directory contains output data from the GFS model v14 or earlier (the GFS spectral
model). Only nemsio format files are available, so there are no file format subdirectories. 

GSMGFS
  2019052000
    gfs.t00z.atmanl.nemsio
    gfs.t00z.atmf006.nemsio
    gfs.t00z.sfcanl.nemsio

The HRRR directory contains output data from the HRRR model. The file formats are based on the
Julian day convention for files stored on the Jet machine:

{yy}{jjj}{hh}{ffhr}{mm}

where {yy} is the 2-digit year, {jjj} is the Julian day, {hh} is the 2-digit UTC hour, and {ffhr} 
is the 4-digit forecast hour.

HRRR
  2020080100
   2021400000000
  2020081000
   2022300000000
   2022300000300
   2022300000600
   2022300000900
   2022300001200
   2022300001500
   2022300001800
   2022300002100
   2022300002400

NAM data is in grib2 format, and follows a standard naming convention from HPSS stores:

nam.t{hh}z.awphys{fh}.tm00.grib2

where {hh} is the 2-digit UTC hour, {fh} is the 2-digit forecast hour.

NAM
  2021061500
    nam.t00z.awphys00.tm00.grib2
    nam.t00z.awphys03.tm00.grib2
    nam.t00z.awphys06.tm00.grib2

RAP input data, unlike all others, has a default "EXTRN_MDL_LBCS_OFFSET_HRS" of 3 in the UFS SRW 
App; this means that the top-level date directory (indicating the initial time of the forecast 
which created the input data) is 3 hours earlier than the initial time of the UFS SRW forecast.

As with HRRR data, RAP data utilizes the julian date format for its output files
standard on the Jet platform.

{yy}{jjj}{hh}{ffhr}{mm}

where {yy} is the 2-digit year, {jjj} is the Julian day, {hh} is the 2-digit UTC hour, and {ffhr} 
is the 4-digit forecast hour.

RAP
  2020073121
    2021321000600
    2021321000900
  2020080921
    2022221000400
    2022221000500
    2022221000600
    2022221000700
    2022221000800
    2022221000900
    2022221001200
    2022221001500
    2022221001800
    2022221002100
    2022221002400
    2022221002700