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Recent Implementations:



Q3FY16 GSM v13.0.2 - implementation completed May 11th, 2016 12 UTC

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:

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.

- (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:


Previous Implementations:



2015011512 GSM v12.0.0 - implementation completed January 14th, 2015

2012090512 Correction to Land Surface Model in Global Forecast System and associated cool and moist bias in near surface temperature and moisture fields (Click to read more)
2012052212 Hybrid EnKF - 3DVar GSI data assimilation (Click to read more)
2011050914 GFS 9.0.1 (Click to read more)
2010072712 T574 W/ NEW PHYSICS - July 27th 2010 (Click to read more)