NOUS41 KWBC 191455 AAA



Public Information Statement 16-34 Amended

National Weather Service Headquarters Washington DC

1055 AM EDT Wed Oct 19 2016


To:      Subscribers:

         -NOAA Weather Wire Service

         -Emergency Managers Weather Information Network


         Other NWS Partners, Users and Employees


From:     Geoffrey Dimego

          Chief, Mesoscale Modeling Branch

          NCEP/Environmental Modeling Center


Subject:  Amended: Soliciting public comments on the removal of

          North American Model (NAM) and Downscaled GFS by NAM

          Extension (DGEX) products through November 11, 2016


Amended to include the removal of the DGEX output, include more

clear changes to the NAM12 and extend the comment period.


The National Centers for Environmental Prediction (NCEP) is

proposing to stop producing some products from the NAM and DGEX;

and to stop disseminating them via NOAAPORT and the NCEP/NWS

servers. The NWS is seeking comments on these proposed changes

through November 11, 2016.


Today output from the NAM is made available from grids ranging

in resolution from 2.5 km up to 190 km. Many of the legacy 

low-resolution grids are available for limited forecast hours

and fields. The same information is provided on expanded grids

with finer-resolution and more variables. Removing these legacy

products is crucial to free up compute and network resources to

distribute newer products. NCEP is proposing to do the



-Remove select NAM and DGEX gridded output products from


-Remove NAM WMO fax charts

-Remove select NAM files from NWS and NCEP servers

-Modify NAM archive period on NCEP server

-Remove all DGEX output


The NWS is currently analysizing SBN/NOAAPORT to determine the

optimal set of products to meet the needs of its forecasters. To

make room for increased spatial and temporal resolution output

we need to remove legacy lower resolution products. This

analysis is being done with every major NCEP model upgrade. With

the next NAM upgrade, currently slated for late December or

early January, NCEP proposes the changes listed below.


1. NOAAPORT gridded NAM products for proposed removal:


Grid   Res      FHs    Area         Map Projection


#218  12 km    00-84  CONUS ICWF*  Lambert Conformal

#242  11.25 km 00-84  Alaska ICWF* Quad Res Polar Stereographic

#207  95 km    00-60  Reg Alaska   Polar Stereographic

#215  20 km    00-60  Reg CONUS    Quad Res. (Lambert Conformal)

#211  80 km    00-60  Reg CONUS    Lambert Conformal

#217  22 km    00-60  Alaska       Polar Stereographic

#197   5 km    00-60  CONUS NDFD   Lambert Conformal

#198   6 km    00-60  Alaska NDFD  Polar Stereographic


*the ICWF products were a limited subset of variables. Not all

grid 218 products are slated for removal. The following will be

the only NAM12 variables removed:


TMAX:2 m above ground

TMIN:2 m above ground

WIND:10 m above ground

WDIR:10 m above ground


DPT:2 m above ground






NCEP will evaluate the need for these grids within the NWS and

will reserve the right to remove them once AWIPS is ready.

Notification will be sent of the exact date of removal.


Users can access the full complement of NAM surface and upper-

level fields on grids #218 (12 km CONUS) and #242 (11.25 km

Alaska) in place of the lower-resolution grids listed above.


WMO headers for these grids slated for removal are listed at:


2. NOAAPORT gridded DGEX products for proposed removal:



Grid   Res      FHs    Area                  Map Projection


#185   12 km    84-192  CONUS Limited ICWF   Lambert Conformal

#186   12 km    84-192  Alaska Limited ICWF  Polar Stereographic

#185   12 km    84-192  CONUS                Lambert Conformal

#186   12 km    84-192  Alaska               Polar Stereographic


These ICWF grids contain a limited amount of near-surface data

fields, most of which are not available in the full DGEX grids



WMO headers for these grids slated for removal are listed at:


3. NAM 00z and 12z cycle WMO Headed fax charts for proposed



Description                    WMO Header  


00 Hour 200MB Isobar/Temp      QHUA17 KWBC

00 Hour 500MB Isobar/Temp      QHTA11 KWBC

00 Hour 700MB Isobar/Temp      QHTA07 KWBC

00 Hour 850MB Isobar/Temp      QHUA04 KWBC

Analysis 300MB Isobar          QHUA15 KWBC


Legacy FAX charts are redundant given the availability of NAM

graphics on the NCEP Model Analysis and Guidance web page at


4. GRIB files that will no longer be provided from the NWS



These products will be removed from the following, with an exact

or replacement product available from the NCEP servers via http,

ftp or grib filter:









All files in this directory are being removed from:




  Where CC is 00, 06, 12, 18

  Where YYYYMMDD is Year, Month, Day

  Where FF is forecast hour from 00-48 or 60


5) GRIB2 files on the NCEP web servers for proposed removal


- nam.tCCz.awip218tiles_fFF.grib2.tar.gz

- nam.tCCz.awip32tiles_fFF.grib2.tar.gz

- tiles.tCCz directory

- nam.tCCz.awip12FF.tm00.10m.uv.grib2

- nam.tCCz.smartakFF.tm00.grib2



  where CC is cycle 00, 06, 12, 18

  where YYYYMMDD is Year, Month, Day

  where FF is forecast hour from 00-84


The tiles are created from the NAM GRIB1 post-processing, which

is being turned off since NAM post-processing will now be done

in GRIB2, from which tiles cannot be generated. Users desiring

subsets of NAM output grids can obtain them via the GRIB filter

utility on the NCEP NOMADS server: (click on "grib filter" option)


6. The current archive of NAM daily directories on the NCEP http

and ftp servers is 30 days. NWS is proposing to limit the

archive to 5 days. This will allow for a better use of disk

space and balance supporting user needs.


The NWS will evaluate all comments to determine whether to

proceed with these changes. If approved, a Technical

Implementation Notice will be issued giving 30 days notice of

the implementation date.


7. The 12 km resolution Downscaled GFS by NAM Extension (DGEX)

run was started in 2004 to provide high-resolution guidance to

the field to 192 hour. Since the GFS now runs at a comparable

resolution to the DGEX and for a longer forecast range, the DGEX

is no longer necessary and the resources used to maintain, run,

and distribute it can be better used for more advanced modeling

systems and products. All NOAAPORT listed above and site

products listed below would be impacted:


Send comments on this proposal to:


     Carissa Klemmer

     NWS/NCEP Central Operations

     Dataflow Team Lead

     College Park, MD


NWS National Public Information Statements are online at: