v14.0.0 - Q3FY17 - July 2017

Global Forecast Systems (GFS) v14.0.0 - Q3FY17 Upgrade

Effective on or about Wednesday July 19, 2017, beginning with the 1200 Coordinated Universal Time (UTC) run, the National Centers for Environmental Prediction (NCEP) will upgrade the Global Forecast Systems (GFS) Analysis and Forecast System as follows:
  - Changes to the model components
  - Changes to the data assimilation and tropical storm relocation components
  - Changes to the post-processing
  - Changes to output products
1) Changes to the Global Forecast System Global Spectral Model (GSM) components:
- Implement GSM source code in NOAA Environmental Modeling System (NEMS) framework.
- Upgrade to asynchronous quilting for scalable and efficient write component in NEMS GSM. Asynchronous quilting means that the model writes out chunks of data to disk in a non-sequential manner. This improves I/O efficiency.
- Replace spectral history file output (sigma files) with new nemsio binary files on model native grid. Documentation of nemsio format including data structure, interface, how to open, read, write, and MPI I/O support are at http://www.emc.ncep.noaa.gov/NEMS/nemsio.php and nemsio library at http://www.nco.ncep.noaa.gov/pmb/codes/nwprod/lib/nemsio.
- Implement Near Surface Sea Temperature (NSST) to replace Real-Time Global SST (RTGSST) to provide more realistic ocean boundary conditions.
- Upgrade deep and shallow convection schemes with scale- and aerosol-aware features along with convective cloudiness enhancement.
- Modify Rayleigh damping to improve temperature and wind forecasts in the upper stratosphere.
- Upgrade the land surface model to increase ground heat flux under deep snow; and unify snow cover fraction and snow albedo.
- Use new high-resolution MODIS-based snow-free albedo, maximum snow albedo, soil type and vegetation type. - Upgrade surface layer parameterization scheme to modify the roughness-length formulation and introduce a stability parameter constraint in the Monin-Obukhov similarity theory to prevent the land-atmosphere system from decoupling.
2) Changes to the Global Data Assimilation System (GDAS) and Tropical Storm Relocation:
- Upgrade GDAS and Ensemble Kalman filter (EnKF) to use nemsio binary files.
- Implement Near Sea-Surface Temperature (NSST) Analysis.
- Implement CrIS full resolution data assimilation capability.
- Implement readiness for new Geostationary Operational Environmental Satellite (GOES-16), Joint Polar Satellite System (JPSS-2) and Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC-2) data assimilation capability.
- Extend Regional Advanced Television Infrared Observation Satellite (TIROS) Operational Vertical Sounder (ATOVS) Retransmission Services (RARS) and Direct Broadcast Network (DBNet) capability.
- Implement bug fix to cloud water increment in Gridpoint Statistical Interpolation (GSI).
- Upgrade land surface type specification in Community Radiative Transfer Model (CRTM).
- Update data monitoring for Megha-tropiques Sounder for Probing Vertical Profiles of Humidity (SAPHIR) and Global Precipitation Measurement (GPM) Microwave Imager (GMI) radiances.
- Assimilate Visible Infrared Imaging Radiometer Suite (VIIRS) Atmospheric Motion Vectors (AMVs) and implement log-normal wind quality control for AMVs.
- Assimilate Geostationary Operational Environmental Satellite system (GOES) clear-air water vapor winds.
- Assimilate additional global navigation satellite system (GNSS)
- Radio Occultation (RO) observations.
- Modify pressure and hybrid coordinates transformation during the storm relocation.
- Change relocation of the vorticity and divergence fields to the relocation of u,v wind components.
- Remove bogus Tropical Storm/Hurricane data for use in Data Assimilation.
- Assimilate Global Hawk dropsonde data when available.
- Upgrade data assimilation monitoring package.
3) Changes to the post-processing
- Upgrade post-processing software to use new nemsio model output.
- Implement continuity equation to derive omega on grid space for new nems model output only.
- Modify interpolation procedure for all categorical fields including land mask, icing severity and precipitation types products to use nearest neighbor interpolation.
- Change interpolation method for In-Cloud Turbulence Potential (CTP) and CB cover (Horizontal Extent of Cumulonimbus) from 'linear' to 'nearest neighbor' to avoid averaging their own specific negative value with normal values when doing grid conversion.
- Users are advised to screen out and not use soil moisture values above 0.468 (the maximum porosity among all soil types) in GFS output files. Values above 0.468 are flag values associated with permanent deep-layer land ice. The land surface model does not predict soil moisture at land ice points.
4) Changes to output products on web services
With this upgrade the following changes occur on either the NCEP web services:
Or on the NWS web services:
- The 2.5km resolution pressure GRIB output files will be discontinued. NCEP has been providing the higher resolution products in order to provide a smooth transition period, but will no longer maintain the resources to continue creating these products. The discontinued output will be:

NWS web: fh.0FFF_tl.press_gr.2p50deg
NCEP web: gfs.tHHz.pgrb2.2p50.fFFF
- The following BUFR dump and prepbufr files will be renamed as described below. There is no change to the file content.

gdas1.tCCz.*tm00.bufr_d.unblok to gdas.tCCz.*.tm00.bufr_d
gdas1.tCCz.*tm00.bufr_d.unblok.nr to gdas.tCCz.*.tm00.bufr_d.nr
gdas1.tCCz.sfcshp.tm00.bufr_d.unblok to
gfs.tCCz.prepbufr.unblok to gfs.tCCz.prepbufr
gfs.tCCz.prepbufr.unblok.nr to gfs.tCCz.prepbufr.nr
gdas1.tCCz.prepbufr.unblok to gdas.tCCz.prepbufr
gdas1.tCCz.prepbufr.unblok.nr to gdas.tCCz.prepbufr.nr
- On the NCEP web services, the EnKF surface analysis ensemble mean file is being discontinued. This file is simply the average of the 80 sfcanl_mem files. Thus, users may still obtain the sfcanl_ensmean content on their own.
NCEP web: enkf.YYYYMMDD/sfcanl_YYYYMMDDCC_ensmean
- The following files will be removed from the NWS websites and the exact same product will instead be available from the NCEP websites listed above. Users are encouraged to migrate to the NCEP sites as soon as possible as all of the products are available currently. Please see below for removals and the associated NCEP site product names:

NWS web removal: fh.0FFF_tl.sflux(.idx)
 NCEP web replacement: gfs.tHHz.sfluxgrbfFFF.grib2(.idx)
NWS web removal: fh.0FFF_tl.press_gr.1p00deg(.idx)
 NCEP web replacement: gfs.tHHz.pgrb2.1p00.fFFF(.idx)
NWS web removal: fh.0FFF_tl.press_gr.0p50deg(.idx)
 NCEP web replacement: gfs.tHHz.pgrb2.0p50.fFFF(.idx)
NWS web removal: PT.sndn_DF.buf/fh.afhr_bs.STN_ID
 NCEP web replacement: bufr.tHHz/bufr.STN_ID.YYYYMMDDHH

Where YYYY is year, MM is month, DD is day, HH is cycle, FFF is forecast hour, and STN_ID is the 6 digit station ID
- On the NCEP websites the number of days of GFS and GDAS datasets available will be reduced from 14 to 10.
- On the NWS web services, the GRIB1 211, 225, FOS 21-24, and WAFS 37-44 grids will be removed from the NWS web service
Where HHHH is the forecast hour, parm is the forecast parameter, and octantX is the WAFS grid letter. Users can find GRIB2 replacement of the WAFS 37-44 grids available in the in PT.grid_DF.gr2/fh.HHHH_tl.press_ar.octantX files.
- Visibility field will be added to the pressure grib files for all resolutions NCEP web: gfs.tHHz.pgrb2.DDD.fFFF
Where HH is cycle, FFF is forecast hour and DDD is for all 0.25 degree (0p25), 0.5 degree (0p50), and 1.0 degree (1p00) grib2 output
- On the NCEP web services, the following changes will occur to the GFS Flux files:

A. Packing has been changed to complex packing to be consistent with packing method of GFS pressure Grib files.
B. These files will be distributed at hourly time steps instead of every 3 hours.
C. Remove category rain (CRAIN) parameter.
D. Correct GRIB2 IDs for soil temperature from "TMP...below ground" to "TSOIL...below ground."
E. Correct GRIB2 IDs for total column cloud fraction from "entire atmosphere (considered as a single layer)" to "entire atmosphere."
F. The time label for SUNSD will be changed to instantaneous to be consistent with time label in GFS pressure GRIB files.
NCEP web file name: gfs.tHHz.sfluxgrbfFFF.grib2
- All GDAS output on the NCEP web servers will be renamed to remove the "1", such that:

gdas.YYYYMMDD/gdas1.tCCz* will be renamed to
- On the NCEP servers, modify the BUFR list of stations from 1919 to 2021 and correct a few errors in the original station list. Land/water designations were added for those stations that do not have the designations. For the full list:
- On the NCEP servers, the station bufr files are now in unblocked format and the file names are changing:
bufr.tHHz/bufr3.STN_ID.YYYYMMDDHH to
Where YYYY is year, MM is month, DD is day, HH is cycle, and STN_ID is station identifier.
- Replace copygb2 by WGRIB2 in downstream pressure GRIB products and change the Grid definition template (octets 43-46) subdivision of basic angle used to define extreme longitude and latitude, and direction increments from 0 to 255 (missing).
NWS web: fh.0FFF_tl.press_gr.DDDdeg
NCEP web: gfs.tHHz.pgrb2.DDD.fFFF
- A second land mask (LAND) is added to GFS and GDAS pressure GRIB files for all resolutions. The second land mask is generated using bi-linear interpolation. NCEP web: gfs.tCCz.pgrb2.DDD.fFFF, gdas.tCCz.pgrb2.DDD.fFFF
- New GFS pressure GRIB files use a very large value of 9.99e+20 to represent the value for the variables that do not have sensible values at any given grid point. For example, soil temperature at a ocean grid point will have a value of 9.99e+20. Users may have to modify their decoding programs to handle such a large value. Files impacted:

NWS web: fh.0FFF_tl.press_gr.DDDdeg
NCEP web:gfs.tHHz.pgrb2.DDD.fFFF
- With the change in nemsio output the following link contains a list of files on the NCEP web services for the GFS, GDAS and EnKF that will be impacted. Users are highly encouraged to download sample data and test:
- Nemsio binary atmospheric files are approximately 2x larger than their sigio counterparts. Nemsio atmospheric files contain data on the native model gaussian grid while sigio files project grid space data into wavenumber (spectral) space. The nemsio binary surface files are approximately the same size as their sfcio counterparts and both representations contain data on the native model Guassian grid.
- With the change in supercomputer architecture for both this upgrade and the following one, there may be some minor (less than 5 minutes) changes in timing of the output files. NCEP will always attempt to deliver products end to end within the expected window, but users are encouraged to re-baseline the output times once we move into operations.
- On the NCEP web site the following additions will be put into NOMADS:

A. The surface flux GRIB2 files will be added to grib_filter.
B. The GDAS pressure GRIB forecast hours will be added to OpenDAP.
- GFS legacy fax chart TIF images will be discontinued on the NWS web service here: http://tgftp.nws.noaa.gov/fax/barotrop.shtml
5) The following changes will be made to NOAAPORT/SBN
- Modify the lists of stations in the GFS BUFR sounding collectives disseminated on NOAAPORT. For the full list please reference this page:
- Replace copygb2 by WGRIB2 and correct the resolution and component flag from 8 to 48. This change applies to the following GRIB2 output on NOAAPORT: 20km CONUS grid; 20km Alaska grid; 20km Puerto Rico grid and Grid 213 (National - CONUS - Double Resolution Polar Stereographic 95km)
- In 2016 NCEP solicited feedback to remove all legacy GFS grids in favor for high resolution 20km and 1.0 deg grids. With this upgrade we will be removing the Alaska Region, North Polar Stereographic - 47.5km (Grid Value #160). The full list of WMO headers can be found here:
To reference the Public Information Statement (PNS) please click here:
- In 2014 NCEP solicited feedback to removal of legacy FAX charts, and at that time we were unable to move forward. So with this upgrade the following will no longer be available on NOAAPORT or GTS:
Winds and temperatures at various flight levels and surface analyses for various domains with WMO headers that match this pattern are being removed:
See the PNS for more details here:
As part of NCEP's standard 30-day parallel testing, the parallel products will be available here:
NCEP urges all users to ensure their decoders can handle changes in content order, changes in the scaling factor component within the product definition section (PDS) of the GRIB files, and volume changes. These elements may change with future NCEP model implementations. NCEP will make every attempt to alert users to these changes before implementation.
Any questions, comments or requests regarding this implementation should be directed to the contacts below. We will review any feedback and decide whether to proceed.
For questions regarding these changes, please contact:
Vijay Tallapragada
NCEP/EMC Modeling and Data Assimilation Branch
College Park, MD
For questions regarding the data flow aspects, please contact:
Carissa Klemmer
NCEP/NCO Dataflow Team Lead
College Park, MD

v13.0.2 - Q3FY16 - May 2016

Global Forecast Systems (GFS) v13.0.2 - Q3FY16 Upgrade

Effective on or about Tuesday May 11, 2016, beginning with the 1200 Coordinated Universal Time (UTC) run, the National Centers for Environmental Prediction (NCEP) will upgrade the GFS Analysis and Forecast System as follows:

  - Changes to the data assimilation components
  - Changes to the model components
  - Addition of hourly gridded output through 120 hours
  - Addition of five layers in the upper stratosphere in gridded output
  - Addition of new product fields
  - Product removals

Read full TIN: http://www.nws.noaa.gov/os/notification/tin16-11gfs_gdasaaa.htm

1) Changes to the Global Data Assimilation System (GDAS):

- Upgrade the 3D Hybrid Ensemble-Variational to 4D Hybrid Ensemble-Variational Data Assimilation System 4D increments are constructed by figuring out best combination of 4D ensemble perturbations. The weights for ensemble members are kept constant throughout the assimilation window. The 4D-Hybrid uses 50 outer and 150 inner iterations with variational quality control turned on after 25 iterations. Tangent Linear Normal Mode Constraint (TLNMC) and Digital Filter Initialization (DFI) are used in the ensembles while additive error inflation is removed. Ozone cross covariances are in the 4D-Hybrid.  Localization is recued to 50 percent in the troposphere and the weights for static and ensemble are kept at 12.5 percent and 87.5 percent respectively.
- Assimilate all sky Advanced Microwave Sounding Unit (AMSU-A) Radiances
- Assimilate Advanced Very High Resolution Radiometer (AVHRR) winds
and monitor Visible Infrared Imaging Radiometer Suite (VIIRS) winds
- Implement Geostationary Operational Environmental Satellites – R series (GOES-R) data readability
- Update Community Radiative Transfer Model (CRTM) to v2.2.1 with
bug fixes in wind direction, use of FAST Microwave Emissivity Models (FASTEM-6 and FASTEM-X) reflection correction for cloudy situations
- Improve bias correction for aircraft observations
- Modify relocation and storm tracking to allow hourly tropical cyclone
- Modify thinning/weight in time for Atmospheric Motion Vectors (AMVs) and radiances
- Upgrade data assimilation monitoring package

2) Model changes to the GFS Global Spectral Model and post-processing software:

- Correct the land surface characteristics for grassland and cropland categories to reduce summertime warm and dry biases over Great Plains
- Upgrade convective gravity wave drag
- Upgrade tracer adjustment in the semi-Lagrangian dynamic core
- Upgrade the NCEP Unified Post Processing (UPP) software to v7.0
- Implement Global Current Icing Potential analysis (G-CIP) products

3) Output product changes

All operational products below can be found on any of following NCEP or NWS servers:


- Add new Global Forecast Icing Severity (G-FIS) icing severity parameter (ICSEV Icing Severity)


    Where CC is 00, 06, 12, 18
    Where FFF is 000 to 384

- Improve Global Forecast Icing Potential (ICIP) products


    Where FF is 06 to 36

- Include hourly forecasts out to 120 hr


    Where FFF is 000, 001, 002, 003, 004...120

- Add grib filter and GDS/OpenDAP availabilty of the 2.5 deg hourly forecasts in NOMADS.

- filter_gfs_0p25_1hr.pl (grib filter link)
- gfs_0p25_1hr (
OpenDAP-alt link)

At this time data will not be available for testing until it goes into operations.

- Add five more vertical levels (7, 5, 3, 2, and 1 hPa) for the variables geopotential height (HGT), temperature (TMP), relative humidity (RH), U- and V- components of wind (UGRD and VGRD) and ozone mixing ratio (O3MR)

  gfs.tCCz.pgrb2.0p25.fFFF, gfs.tCCz.pgrb2b.0p25.fFFF
  gfs.tCCz.pgrb2.0p50.fFFF, gfs.tCCz.pgrb2b.0p50.fFFF
  gfs.tCCz.pgrb2.1p00.fFFF, gfs.tCCz.pgrb2b.1p00.fFFF

    Where FFF is forecast hours from 000 to 384

- Replace 775 hPa state variables with 750 hPa in the GFS WAFS grids 37-44 for UGRD, VGRD, TMP, RH, HGT

  On NCEP Servers:


  On NWS Servers:


    Where FFF is 000-120

- Add GDAS ABIAS air BUFR file


- Modify the list of stations on NOAAPORT and NCEP servers, for which BUFR data are generated for the GFS.  The changes will also modify the lists of stations in the GFS BUFR sounding collectives disseminated on NOAAPORT. For the full list please reference this page:


The following changes to NOAAPORT are detailed below with the following WMO headers for each grid:


- Alaska region grid 217 (20km) has been modified to expand latitude from 30N to 35N and longitude from 173W to 170W.

- The Maximum and Minimum Temperatures (TMAX, TMIN) Product Definition Template 4.8 will correct a mistake in the second fixed surface from “255 0 2” to “255 0 0” for the following grids:

  Alaska region 20km
  Pacific region 20km
  Puerto Rico 0.25deg
  CONUS 20km

- The Water Equivalent of Accumulated Snow Depth (WEASD) WMO headers were incorrectly labeled for forecast hours 186, 198, 210, 222 and 234. The following changes will be applied to each grid below:

  CONUS 20km: LSRU98 -> ZSNZ98
  Alaska 20km: LSRU98 -> ZSBZ98
  Pacific Region 20km: LSRU98 -> ZSEZ98

  Puerto Rico 0.25deg: LSRU98 -> ZSFZ98

- The Alaska region grid 217 (20km) had some incorrectly labeled forecast hours in the grid identifier WMO header. This will be addressed so all Alaska WMO products have A1 = B

- Addition of GRIB2 20 km gridded product over Pacific Region (Mercator) to NOAAPORT

  Runs 4 times per day at 00z, 06z, 12z and 18z

  WMO headers will be as follows:

  T1 = Y for forecast hours: 00, 06, 12, 15, 18, 24, 30, 36, 42, 48, 60, 72, 84, 96, 108,120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240

  T1 = Z for forecast hours: 03, 09, 15, 21, 27, 33, 39, 45, 51, 54, 57, 63, 66, 69, 75, 78, 81, 90, 102, 114, 126, 138, 150, 162, 174, 186, 198, 210, 222, 234

  T2 specifies the parameters as follows:

     T = Temperature, TMIN, TMAX; H = Height;
     5-wave geopotential height; O = Vertical velocity;
     R = Relative humidity; C = Absolute vorticity;
     U = u-component of wind; V = v-component of wind;
     P = Pressure; Pressure reduce to Mean Sea level;
     B = Vertical speed shear; E = Total precipitation;
     G = Convective precipitation; Q = Best Lifted Index;
     W = Convective Available Potential Energy;
     Y = Convective Inhibition; X = Surface Lifted Index;
     F = Precipitable Water; M = Precipitable Water;
     S = Water Equivalent of Accumulated Snow Depth;

  A1 = E* Grid 20 km, Pacific Region

  *Was incorrectly labeled "F" in the previous advertised TIN 14-54

  A2 specifies the forecast hours as follows:

     A=00; B=06; C=12; D=18; E=24; F=30; G=36; H=42;
     I=48; J=60; K=72; L=84; M=96; N=108; O=120;
     P=132; Q=144; R=156; S=168; T=180; U=192; V=204;
     W=216; X=228; Y=240 (Note: T1 is Y)

     B=03; E=09; H=15; K=21; L=27; O=33; P=39; Q=45;
     R=51; M=54; S=57; Z=63; N=66; Z=69; Z=75; T=78;
     Z=81; U=90; V=102; W=114;
     Z=126; 138; 150; 162; 174; 186; 198; 210; 222;
     234 (Note: T1 is Z)

    ii specifies level as follows:

     99=1000mb; 93=975mb; 95=950mb; 92=925mb; 90=900mb;
     91=875 mb; 85=850mb; 82=825mb; 80=800mb; 77=775mb;
     75=750mb; 72=725mb; 70=700mb; 67=675 mb; 65=650mb;
     62=625 mb; 60=600mb; 57=575mb; 55=550mb; 52=525mb;

     50=500mb; 45=450mb;40=400mb; 35=350mb; 30=300mb;
     25=250mb; 20=200mb; 15=150mb; 10=100mb;
     73=High, Mid, Low cloud bottom level; 86=Boundary Layer;
     89=Reduced to Sea Level; 94=Level of the 0 deg. C isotherm;
     96=Maximum wind level;
     97=Level of the Tropopause, potential vorticity surface;
     98=Surface of Earth; 00=Entire Atmosphere

  See the following link for a full list of WMO headers:


4) Output product removals

NCEP has been working to remove low resolution legacy products in lieu of higher resolution grids. Last year NCEP added new higher resolution grids to NOAAPORT in preparation for removing the legacy grids. Due to the positive responses received from the NCEP Public Information Statement 16-04, Removal of Legacy Global Forecast System (GFS) Gridded Output, the following products will be removed with this upgrade:

- Remove the GFS grid 212, 40km Regional CONUS from NOAAPORT

  WMO Headers:


To find the replacement products please reference this TIN:


- Removal Vessel Sea Ice and Fog on grid 232, 1 deg Northern

Hemisphere from NOAAPORT

  WMO Headers:


- Removal of 1.25 deg GRIB1 GFS WAFS products from the NWS

http/ftp server:





  where CYCLE is 00, 06, 12, 18
  where YYYYMMDD is Year, Month, Day
  where FFF is forecast hour from 000-120

To find the replacement product please reference this TIN:


- Removal of 1.25 deg GRIB1 GFS WAFS products from the NCEP

http/ftp server:


To find the replacement product please reference this TIN:


5) Parallel data available

Starting in April 1, 2016 all parallel data sets will be available on the following servers:


For more information on this GFS upgrade, please see EMC real-time and retrospective parallels and verification pages:


NCEP urges all users to ensure their decoders can handle changes in content order, changes in the scaling factor component within the product definition section (PDS) of the GRIB files, and volume changes. These elements may change with future NCEP model implementations. NCEP will make every attempt to alert users to these changes before implementation.

For questions regarding these changes, please contact:

     Vijay Tallapragada
     NCEP/Global Climate and Weather Modeling Branch
     College Park, MD



For questions regarding the data flow aspects of these data

sets, please contact:

     Carissa Klemmer
     NCEP/NCO Dataflow Team Lead
     College Park, MD



NWS National Technical Implementation Notices are online at: